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Mound Systems
Other Alternative Systems
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If the lot does not pass the perc test, some municipalities may allow you to build an alternative engineered system. Alternative systems may also be required on waterfront properties and other environmentally sensitive areas to help protect water sources.
Where the problem is soil that is too dense, too shallow over bedrock or hardpan, or the water table is too high, a “mound” system is often the first choice as it works much the same as a standard system, only with the leach field raised above the natural grade.
Alternative systems cost more because they have more moving parts and electrical components (pumps, monitors, alarms) and greater complexity. They require greater monitoring and maintenance to prevent problems. They also require expert design and installation. If either the designer or the installer is unfamiliar with the technology being used, it may not perform as intended.
There is no one-size-fits-all solution. Design of a system is specific to the soil type, site conditions, and usage levels. Make sure your designer and installer both have proven track records with the specific system you are using.
Some states and municipalities only accept system types certified in their jurisdiction and may require that the owner maintain a service contract with an approved vendor. Proper maintenance is critical for success with alternative systems.
MOUND SYSTEMS
The mound uses a series of small distribution pipes set in a layer of gravel on top of a layer of sand, typically one to two feet deep. The tops and sides are covered with topsoil (see illustration). A mound system has one extra component, a dosing chamber (also called a pump chamber), which collects wastewater coming out of the septic tank.
Using a pump and a float system, the dosing chamber pumps effluent at a controlled rate for uniform distribution into the leach field. Most have an alarm system that alerts the owner, or maintenance company, if the pump fails or the water rises too high in the tank. Observation tubes are also recommended which allow easy inspection of the tank without digging up the access port. Also monitoring wells are often installed to monitor the conditions in and around the leach field.
The biggest costs are the additional equipment as well as the earthwork and extra materials needed to build the mound. Depending on the system design and the local cost of sand and gravel, a mound system can add $10,000 or more to the price of a conventional system – often costing over $20,000 in some areas.
Also, mound systems require more frequent pumping and more monitoring and maintenance because of the added complexity. Annual maintenance costs can be as high as $500.
OTHER ALTERNATIVE SEPTIC SYSTEMS
There are a wide range of alternative septic systems on the market and new ones arriving all the time. Some are geared more to community systems serving several homes and are usually monitored and maintained professionally by a service company.
Some alternative systems are well-suited to individual homes, although the cost, complexity, and maintenance of these systems need to be carefully considered. Most use electric pumps or siphons as well as filters, all of which need more monitoring and maintenance than a traditional system.
Some larger community systems use pre-treatment of the effluent before it reaches the leach field, a mini version of a sewage-treatment plant. But most single-home systems rely on bringing in natural or manufactured materials that require less surface area for leaching than the poorly draining native soils would require. There are many variations and combinations of systems and components used including:
- Pressurized dosing: This uses a holding tank and pump to force the effluent though the distribution piping more evenly and in controlled doses, improving the performance of the leach field. It can be used to rehabilitate a leach field or in combination with other systems such as a mound system, sand filter, plastic leach fields, or drip irrigation.
- Plastic chamber leach field: This is a standard septic system with an alternative leach field, which may be downsized in some jurisdictions, making it well suited to small building sites. The half-pipe plastic chambers create the void for effluent flow, so no gravel is needed. One example, the Infiltrator System, has been in use for over 20 years, and according to the company can support traffic loads with only 12 inches of compacted cover. The additional cost of the plastic components is partly offset by the savings on gravel and smaller size of the drain field.
- Sand filter: This is a large sand-filled box, 2-4 ft. deep, with a watertight liner of concrete or PVC. The sand is used to pre-treat effluent, by filtration and aerobic bacteria, before disposal to the leach field. The boxes are usually partially or fully in the ground, but can also be above-grade when required. In the most common configuration, a pump and controls are used to evenly dose the effluent on top of the filter, although gravity distribution is possible in some cases. The treated effluent is collected at the bottom where it is pumped or gravity-fed to the drain field.Some sand filters recirculate the effluent back to the tank several times before distributing it to the drain field.Most sand filters are used for pre-treatment, but they may also be designed as the primary treatment. This is called a “bottomless sand filter” as the effluent passes directly into the soil beneath the filter (see photo above). Sand filters must be well-engineered and constructed, and properly maintained, to avoid frequent clogging of the sand. Read more on Sand Filters.
- Aerobic treatment system: These systems use an aerobic process to treat the effluent, typically using an multi-chamber concrete tank placed underground. The most complex systems contain four chambers to collect, aerate, purify, and pump the effluent. The first chamber acts like a smaller version of a traditional septic tank. In the second “treatment” tank, an air pump is used to constantly inject air into the effluent. The air supports the growth of aerobic bacteria which process sewage more efficiently than the anaerobic bacteria in a typical septic system. In some systems, a third and fourth chamber are used to further clarification and pump out the purified water. So-called “fixed-film” systems also use a synthetic media filter to enhance the bacterial process.When properly maintained, aerobic systems can produce higher quality wastewater than a traditional system and may include an added disinfectant before the purified wastewater is discharged. Discharge may be to a reduced-size drain field or sprayed over a large area in rural settings. Technically these are mini sewage-treatment plants rather than septic systems, which rely mainly on anaerobic treatment. They are often referred to as ATU’s (aerobic treatment units) or BATs (best available technology units). These systems are expensive to install and maintain, so are mainly used where high-quality treatment is needed in a limited area or with poor soils. They are becoming more common on waterfront properties. Read more on Aerobic Treatment Systems.
- Drip distribution/irrigation: This uses a pump to distribute effluent through a filtering device to an array of shallow drip tubes spread over a large area. A pretreatment unit is usually required to deliver relatively clean water to the system. The water may used to water a lawn or non-edible plants, which remove the nitrogen from the wastewater. This type of system can be used with shallow soils, clays, and on steep slopes. Because the tubes are near the surface, freezing can be a problem in cold climates. As with other alternative systems, expect high installation costs, along with extra monitoring and maintenance.
- Constructed wetlands. For the ecologically minded who want to play an active role in recycling their wastewater, these can work in almost any type of soil. The system uses a man-made shallow pond, which is lined and filled with rock, tire chippings, or other media. The media provides a habitat for special plants that treat wastewater and provide a pleasant environment. Wastewater from the septic tank is distributed by a perforated pipe across the media bed, where plant roots, bacteria, and other microorganisms break down the pollutants. A second pipe at the back of the wetland collects the treated water. The homeowners must plan to spend time planting, trimming, and weeding the wetlands area.
Related links: National Small Flows Clearinghouse Inspectapedia.com
See also:
Who Should I Hire For Perc Test?
Are Alternative Septic Systems Allowed?
How Long Do Septic Systems Last?
How Much Slope For Septic Line?
Inspecting a Septic System
Perc Test: Best Time of Year?
Sand Filter for Existing Septic System?
Testing for Well & Septic
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A. Onysio says
Cure For Saturated Leach Field?
We purchased a lot in July 2022 and had a perc test done just prior to the closing. The perc test was successful. We built a home and moved into it in July 2023. In January 2024, our temps froze in Alabama and we were dealing with alot of precipitation, and still are. We noticed sluggish toilets and found our septic was full in January and had it pumped. 2 weeks later it needed pumped again. We have been told that there is too much surface water and that the leach fields are saturated. The most recent thought is that we have a hardpan of soil that is preventing proper drainage. We are still weighing our options on resolution. One option is the breaking of the hardpan. The other is a mounded system. I am wondering if anyone has any experience with breaking the hardpan and if they can tell me how we would know if that has been broken. Is it just that we would know by no longer having problems? Can you advise on which solution or others may be a more permanent fix to the saturated leach fields?
buildingadvisor says
Most septic regulations, which vary from town to town, require that a leach field be build on undisturbed, native soil, and that the trenches be at least 3 ft. above the “limiting zone” caused by hardpan, the seasonal high water table, and other conditions that impede drainage. These conditioned are typically determined before designing the septic system by visual observation during the Deep Hole Test. This test works in conjunction with the perc test which measures how fast the soil can absorb the effluent.
Assuming these tests were done correctly and that the system was professionally designed and installed, The most likely explanation it that excess surface water is much greater than the system was designed to handle.
After consulting with the system designer and town authorities, my first step would be to limit the intrusion of surface water into the drainfeld area. Our section site drainage shows a number of relatively low-cost ways to achieve this. On difficult sites, curtain drains around the drain field have proved successful. You may wish to hire the same septic system designer or a soils engineer to oversee the “dewatering’ of the site.
If this is not an option, your best alternative may be a mound system, described in the article above. This increases the depth of well-draining soil before encountering hardpan or a high water table.
I have not heard of anyone breaking up the hardpan in active or new drainfield. Modifying the soil under a septic system is usually prohibited, except in certain engineered solutions.
Doug Merrick says
Can I Turn Off Lift Pump If House Winterized?
Can I safely turn the power off to my septic system over the winter? This is a 1200 sq ft summer home. The is no septic use from November to April. My tank is triple chambers with a raised septic field. Temperature in winter rarely goes below 0celcius
Dayam says
What Are the Pros & Cons of Tertiary Treatment?
Hi,
We are waiting to do a perc test when the soil is not frozen and analyzing 2014 perc test results before buying the land in question.
we put an offer on a land near Lake Crooks in Québec, Canada, with the condition of obtaining a positive perc test. The perc test that was performed in 2014 states that the conditions encountered on the site are not favorable to the installation of a septic tank with infiltration due to the presence of rock on the entire area under study.
They recommended a tertiary treatment including phosphorus removal and passive disinfection with a sand filter as well as a discharge by infiltration. Can you please provide me with more clarity on the pros and cons of that kind of tertiary septic system? We don’t want to have any surprises and want to prepare accordingly. Thank you!
buildingadvisor says
Sounds like you will need a costly and complex septic system, if one will be allowed at all. If the site is not favorable for an infiltration (chamber) system, then it would not be suitable for conventional gravel trenches either. The goal of the tertiary treatment would be to purify the effluent to the point that it can drain safely into the less-than-ideal soil in your drain field.
The need for tertiary treatment may indicate the need for further disinfection or the removal of the nutrients nitrogen and phosphorus — or for both disinfection and nutrient removal. These nutrients, found in fertilizers, can cause excess algae growth in nearby bodies of water. Conventional septic systems remove most of the pathogens from the effluent, but do not remove nitrogen and phosphorus. Several states are starting to require homes built near open bodies of water to address this.
There are many approaches to tertiary water treatment, including sand filters, aeration, disinfection, and ATUs. Research is under way to study the effectively of low-cost wood-chip bioreactors, which can remove most of the nitrogen and some of the phosphorus. All of these systems add to the cost, complexity, and maintenance requirements of your septic system.
What type of system, if any, will be suitable for your site is up to the local health department (or whoever oversees septic system permits) and what equipment your local septic system designers are comfortable specifying. Neither the health department nor the designer wants to go out on a limb with technology untested in your area.
As for cost, you can expect to at least double the cost of a conventional system. I’ve recently seen several run over $50,000, plus more frequent maintenance. Prices may be less in lower-cost regions.
Bottom line: Take your new perc test results to the local health department to see what, if anything, they will allow on this site. Next, visit a local septic system designer to see what type of system they recommend, and what they think it will cost to install and maintain.
They you can proceed with your eyes open.
yannick neveux says
Any Septic System Suitable for Floor Plain?
I inherited a lot in Pennsylvania just on the edge but within the 100 year flood plain. The city is saying that according to the Department of Environmental Protection the construction of new septic systems for new homes that are within the 100 year flood plain are not permitted. Is there any option? Thanks
buildingadvisor says
Many areas do not allow new septic systems to be built in 100-year flood plains. And redrawn flood maps are placing more land in these restricted areas. So you are fighting an uphill battle.
Floods are very hard on conventional septic systems. Tanks can fill with debris, or may become dislodged and float downstream. Absorption fields are often damaged or clogged with silt and need replacement. Some components may survive or you may need a complete new system.
There are two separate issues to consider:
1) Is there a system that will work in flood-prone areas?
2) Will my local jurisdiction allow this system to be used?
Every city, town, county, and state has it’s own set of regulations for on-site sewage systems, so you really need to contact your local permitting authority — often the health or environmental department — to find out what might be allowed in your area. Most jurisdictions have a list of alternative septic systems that are acceptable in their area under specific conditions.
With the backing of a licensed engineer or septic system designer, you may be able to submit a system not expressly allowed and seek to demonstrate compliance with existing standards. The town can accept or reject your plan or ask for modifications. And any decision can be appealed, but it is a long shot that the town will accommodate you in this situation.
In areas with high water tables, the most common drain field system is a mound. However, with floodwaters rising well above the ground surface, a mound system would fail and, in fact, could be washed away or severely damaged.
Septic tanks are another problem. Depending on the air content in the tank during the flood, the tank may have enough buoyancy to work itself loose and float downstream. Anchoring devices can be used to help prevent this outcome – or the tank could be located above ground. Using an above-ground system with waterproof electrical components (for one or more pumps and alarms) is a possibility – if you can engineer a raised bed with sufficient height and protection to maybe survive a flood.
karen massengale says
What Are Options With Failed Perc Test?
We have a lake lot to sell with no septic system. The county is also saying no mound septic is allowed. The land does not perc…any suggestions?> At this point, we have no idea what to do with it….its on year-round water and the houses that were built on both sides were grandfathered in and were able to put in septic tanks.
buildingadvisor says
Sorry to hear about your situation — a failed perc test in never good news.
You said that the county is not allowing a mound system. First thing I would do is schedule a meeting with the authority that grants septic system permits in your area (usually the health or environmental department) and ask if any type of alternative system would be allowed. There are a lot of options available and some are allowed in some jurisdictions, but not others.
I would also ask if there would be any way to build on the lot — for example, with a pump-out tank — not a desirable approach, but maybe acceptable for a vacation cottage. I would also ask if a mobile home or any other type of dwelling unit might be allowed. Ask also whether there is any chance of obtaining a zoning variance that would allow some type of on-site sewage system.
On a larger lot with more than one potential site for the leach field, you can try an additional perc test at one or more areas on the site. You can also try to retest during a drier season, if that is allowable by the county. Another long shot is asking an abutter if they would consider granting or selling you and easement to place your drain field on their land. The septic tank would still be on your lot.
If none of these options pans out, then you are faced with the prospect of selling an unbuildable lot. Under modern disclosure laws, you will probably need to make it clear to prospective buyers that the lot has failed to perc and is classified as unbuildable.
The most likely buyer for an unbuildable lot, in my experience, is an abutter who may want the land to enlarge their existing lot or create a buffer. In a vacation area, the land may have some value for campers or other recreational uses. There may also be agricultural or commercial uses such a storage garage – without a sink or bathroom.
But, in any case, the value of an unbuildable lot will be a fraction of the value of a residential building lot.
Alan Kidwell says
Perc-Rite drip dispersal could be a suitable solution for your situation. Call Alan Kidwell at American Manufacturing 434-907-0130
MH says
Will Failed Perc Test Qualify for Alternative System?
Hello. I’m looking to purchase land in Lusby, MD, in Calvert County. It failed a perc test but I need to know if there is gaurantee or hope of getting it approved for an alternative septic system. First time buyer here, greetings.
buildingadvisor says
NO! There is absolutely no guaranty that you can get approval for an alternative septic system. Also be aware that alternative systems cost a lot more to build and maintain.
I would make any offer to purchase contingent on approval to obtain a septic system permit. The next step would be to bring the test results to the city/county department that issues septic permits (usually the Dept. of Health or Environmental Quality).
Get their opinion in writing. It’s possible that you cannot get an official opinion without an engineered septic system design which will cost you $500 to $1,500, depending on local costs and the complexity of your system. It will also take time to get a design. Maryland is one of the stricter states with septic system regulations, so proceed with caution.
Unless this is a fantastic building site at a fantastic price, your best option might be to just walk away.
Kevin Scott says
Any Way to Run Driveway Over Drain Field?
I have read through the comments here and I think that I may have encountered the worst possible scenario ever with a septic system and I am looking for a way out besides Foreclosure as I hold a Government Security Clearance which could be lost due to the situation that I am in.
I am in the Fredericksburg area of Virginia and went to sell my home. I was advised that in Virginia the seller is responsible for performing a septic system inspection and so I paid the $600 to have that task done.
The septic company said that the system was old and needed to be replaced or repaired. Rough news for most right? No, that was just the beginning.
It was then identified that the drainfield goes onto someone else’s property and there is no easement for the drainfield. To make it worse, the neighbor refuses to grant easement
even though he doesn’t live there and it is just a big rural field. I have also asked the neighbor to buy my house and there is no interest. I recently uncovered from the County courts record division that the septic system was “illegal” when it was built back in 1950. The County contacted the owner, the owner responded but it never seemed to have been rectified. Additionally, the house is in the Chesapeake Bay preservation area which complicates things a bit more.
So I went to the soil guy (AOSE) who mentioned that the only way I could run a system of any type is to run a conventional on the neighbor’s property. That soil guy then proceeded to ghost me.
Every soil guy (except for the one who actually showed up below) I talked to in the area refuses to come check out the house saying that there is no alternative system that will work at my home at any price.
So we took the neighbor to court to try and get an easement. Litigation is in process but we are losing and the process is likely to drag out for another year (it has been a year already).
The judge granted us an order to have the AOSE take a look at the ground to see what would perk. Unfortunately the only area that would perk is right through my existing driveway. There would be no way for cars to enter the house without running over the drainfield. I asked the soil guy if there is any way to protect the drainfield from that and the answer was no. I think that there has got to be some way to protect the drainfield.
I really feel like there is more work than I can shake a stick at for the soil guys and septic system folks so I am being limited to obscure resolutions and the pool of professionals that are willing to interact with me. The cost to go through my driveway which is not reasonable is more than 30k plus design fees.
Any ideas besides returning this lemon to the bank and taking my chances that I can explain the totality of circumstances to my Security Clearance Officer?
Thanks.
buildingadvisor says
Sorry to hear about your situation – sounds like a real nightmare.
You live in an area with very stringent septic system regulations and strict enforcement, and it sounds like no one is interested in working with you develop a workable plan. In my experience there is almost always a workaround if the authorities are open to new approaches.
However, first you need a licensed designer (or product manufacturer) who is willing to go to bat for you. Doesn’t sound like that is in place. You may also need to apply for a special permit or variance for a system that falls outside of the normal parameters.
I am not a septic system designer and don’t know the specifics of your plan, but a few things come to mind.
In some areas, vertical leach pits are an alternative to horizontal leach fields where space it tight and the soils are suitable. Unlike drain fields, leach pits can be driven over as long as the components are traffic-rated for H20 loading. That includes a heavy concrete lid. I had this type of system installed 25 years ago (in the middle of a gravel road) and have not had a problem.
A couple of other thoughts:
– Any way to relocate the driveway so it does not interfere with the drain field?
– Could you have two separate drain fields on either wide of the driveway, connected only by a pipe under the driveway. I know that some areas allow you to run the septic drain line under a driveway, although the drain field trenches must not be driven over.
– Several types of alternative systems allow you to reduce the size of the drain field. Would one of these allow you to find adequate space not under your driveway?
Seems like your first step is to find a septic system designer willing to work with you come up with an innovative plan that will be acceptable to the town.
Hope you’re able to find that person and move forward with this. If you come up with a well-engineered plan that the town does not accept, then you may need to consult a lawyer as well – not to get an easement, but to get a variance that will allow the system to be installed
Bryce says
Sounds like would be most cost effective to install composting toilets – no septic needed;
kitty finnigan says
My thoughts too. Bryce. The other water gray water could be used for watering gardens, etc. I think..
Nellie says
This may be a complete long shot, but since the drainpipe has been on the property since 1950, you may have squatters rights. I’m not sure about Virginia law, but in Massachusetts if something you own is left on someone else’s property for more than 20 years without the property owner saying anything, you have rights to that property. If Virginia has a law like this you might be able to use it to get an easement, or at the very least make it very difficult for your neighbor to force you to move your leaching field off their property. I could be totally wrong, but I figured I’d respond to your post anyway as you seem to have reached the try anything stage of desperation. I hope it helps and hopefully you figure everything out without having to spend a ton of money.
buildingadvisor says
This refers to the strange legal principle of “adverse possession”. Under this common law rule, a person can claim legal title to land that they have openly used for a number of years without the permission or objection of the landowner. The number of years and other conditions vary by state, but the timeframe generally ranges from 20 to 30 years. You would need to sue the owner and prove your claim in court to gain title. You can read more on taking land though adverse possession at this link.
Miriam Moore says
What solution did you ultimately come up with? I’m having a similar problem on a recently purchased waterfront property in Texas. I’m thinking of installing incinerator toilets (which are expensive) and a grey water tank, which is normally required to have a just-in-case diverter valve to a septic system, but the only way I can have a septic would be a holding tank. I have found various toilet solutions but for gray water there are few options. The EcoJohn central incinerator can take gray water but it starts at 10k. That doesn’t seem worth it for a vacation property that only gets low seasonal use, so I’m hoping to find something workable for less than that.
shawn griffis says
Buying House With Holding Tank
So i want to buy this house on the Eastern shore of Maryland. The county is telling me the only septic I can have in this area (deemed critical area 3 marsh lands/wet land) is a holding tank. The holding tank there now was never permitted and is only 500 gallons. If i purchase the property could you give me some links or help with this? i would like to sell it eventually. Its a 1 bedroom, 1 bathroom 589 sf hose on 20 foot stilts right in the marsh. The water views are 36o degrees located right in the middle of a wildlife preserve which means no neighbors at all YEAH!
buildingadvisor says
Sounds like a beautiful spot, but I would think twice about building on a site that requires a holding the tank for onsite sewage. Sounds like you will need to get a permitted tank installed, and then will need to pump it out every 1-2 months depending on tank size and your level of usage.
Find out why the current tank was not permitted and what you will need to do to get a properly permitted system.
If you get a 1,000 gallon tank and are extra careful about water conservation, maybe you can stretch that a bit. Still you can expect to spend $100 to $300 per pump-out. Call around for prices.
You’ll also want an alarm to tell you when the tank is full unless you’d rather use a dipstick.
Also, you may have some difficulty selling a lot with all a holding tank.
Most homeowners want a functioning septic system or a tie in to a municipal sewer.
Also find out about the water supply. Is there a functioning well or do they bring in bottled water — another issue that could affect resale as well as your quality of life.
Lori says
Chamber System Failed in 15 Years
Our chamber septic system was installed 15 years ago when we built our house. The design used 19 truckloads of sand instead of gravel. We pumped the system regularly.
Now that we are selling, we did an septic inspection and discovered that the system is over-saturated and needs to be replaced or rehabbed at a cost of over $10,000.
We have come to believe that chamber systems are not a good design. Any information on this type of system would be appreciated.
buildingadvisor says
A chamber system uses engineered plastic chambers in the drain field instead of perforated plastic pipe set in gravel trenches. In most installations, the chambers rest on native soil, dispersing the effluent directly to the soil. Chamber systems work best in granular, well-drained soils.
These systems are sometimes used on small sites as some jurisdictions allow you to reduce the size of the drain field. They are also used on steep sites and other conditions where gravel is impractical or too expensive.
While the manufacturers of these systems claim that they are more efficient than traditional systems and can use a smaller drain field, independent studies have been mixed. Please CLICK HERE FOR THE FULL DISCUSSION OF THIS TOPIC.
Lori Maurer says
Yes it absolutely has settled some and collects some water. However after 15 years, our home is under contract, and we’re about to replace the field bed. What choices would you suggest for remedying it? Would you hold the original installer/engineer accountable in some capacity?
Richard Piluk says
You should be able to salvage the 19 truckloads of K4 sand and reuse your the disposal bed. If the chambers have settled and are now full of sand they will need to be dug out and replaced with a new distribution system. You should find that the sand just inches below the chambers is relatively clean.
Once the chambers are removed and the clean sand is exposed, you will need to work with the local regulators and engineer to resign a new distribution method for the system. If the same distribution system is recommended, chances are the new chambers will not settle again since the sand should now be compacted after 15 years. I would recommend using far fewer rows of chambers and backfilling them with clean pea gravel instead of sand. The pea gravel will give more structural support to the chambers and eliminate the possibility of sand entering the chambers from the sides. There are ways to improve the infiltration of the wastewater into the sand below but they will need to be reviewed and approved by your local regulators.
Caleb Krebs says
Is It Worth Perc-Testing Another Location After Failed Test?
I have a mountainous piece of land that I was told is non-percable. 75mpi. Any ideas. They said I could try another location, but the terrain is fairly uniform.
buildingadvisor says
For starters, I would talk to the local authority in charge of issuing septic system permits — usually the town’s health or environmental department — to find out what the rules are in your area for conventional and alternative septic systems.
The cutoff for conventional systems is 60 mpi in many areas, but is higher is some. With a perc test result of 75 mpi, you should be able to install an alternative system, especially if you have a relatively flat area for the leach field. The downside is additional cost for installation and maintenance. Most alternative systems have pumps and other moving parts that need careful monitoring and maintenance.
If the lot is large enough, it might be worth testing another location on the site. There can certainly be variation below grade, even if the terrain looks fairly uniform. The soil testing company, or a local septic system designer or soils scientist would have better insight into local soil conditions. Sometimes you can find someone in the dept. of soils science or agronomy at local college to take a look for free.
To save money, you can conduct a DIY perc test in a few locations to find the most promising site for your leach field. It’s not all that difficult, but you’ll have to haul some water to the area to saturate and fill the holes. If you get lucky and find permeable spot, then go ahead with an officially sanctioned perc test.
carol shupe says
Can One Well and Septic System Serve Multiple Homes?
Can you connect two small houses to on septic system and one well?
Thanks
buildingadvisor says
“Community” wells and septic systems that serve multiple homes are quite common. From a technical standpoint, there is no problem with multiple houses taking water from the same well or discharging sewage to the same septic system. There are a few issues to consider:
1) The well and septic system must have adequate capacity to serve all the homes tied in. Proper engineering for multiple users is essential.
2) The multiple users must have legal agreements defining rights and responsibilities for using and maintaining the systems. This might involve easements or other legal agreements covering the shared ownership and/or usage.
3) The well and septic system must be maintained properly for long-term performance. For alternative septic systems, a maintenance contract is highly recommended.
4) The town or municipality must approve your plan.
For two small houses, sharing should not be a problem – especially if you own both of the houses. Where multiple owners are involved, in addition to legal agreements, it’s essential that the users have a shared commitment to proper usage and maintenance. For example, if one user is dumping chemicals, bacon grease, and other solids down the drain, it’s going to harm the system used by all. Or if one family is consistently drawing more than their share of water, other uses may face shortages. Best to have a meeting of the minds of all participants before going this route!
Debra says
Second Mound System Failed Like the First One
I am on my second sand mound and it’s failing at the foot just like the first. I have standing water. I’ve done everything by the book as far as caring for it. No toilet leaks, space out laundry with low water capacity washer, nothing put down the drain that shouldn’t be, low water use shower heads and toilet tanks. I filter my laundry water to remove lint. No chemicals. Honestly, very little water use compared to my neighbors with 4 kids. Still, the second one started failing just a few years after install. Only 2 of us in house.
buildingadvisor says
Sorry to hear about your situation. It sounds very frustrating and expensive. It also sounds like you’ve done everything right as the homeowner, so the source of the problem lies elsewhere. In most cases, a properly designed and built mound system should last at least 20 to 30 years with proper maintenance.
Mounds are typically used where the native soil is too dense for a standard drain field, or the bedrock or water table is too close to the surface. Mound systems may also be used where the soil is so porous that a standard system would pollute the groundwater. It would help to know why a mound system was used in your case.
Other than misuse by the homeowner, the main causes of premature failure of mound systems are design and siting errors, faulty construction, and inadequate materials – especially the sand.
Seepage at the base of the mound indicates that water is “ponding” there. This indicates that the system cannot process the effluent fast enough. Either the load is too great, the system is clogged, pipes are leaking, or surface water is infiltrating the system.
Design errors could include:
• Insufficient sand in the mound
• Less than one foot of native soil above bedrock or the high water table.
• System is sited so that surface water is draining into the mound area.
• Water from the roof or paved areas is draining toward the tank or mound.
• The absorption area is too small for for the site conditions.
• The mound was not designed properly for the slope and contour of the land.
Construction errors could include:
• Excavator compacted or smeared the native soil under the mound during construction.
• Native soil was too wet during construction of the mound.
• Vegetation was not removed in the mound area.
• Drain pipes have cracked or disconnected.
• Leaky joints in the septic tank or dosing chamber.
• Problems with dosing pump, dosing frequency, or float adjustment.
• Sand in the mound does not comply with standards for particle size and distribution.
Some commonsense steps you can take include:
• Make sure that roof runoff and other surface water is diverted away from the tank and mound.
• Plant grass on the mound surface to help prevent erosion.
• Keep trees and deep-rooted plants a safe distance away from the mound.
The system should have monitoring ports that allow your service company to monitor the ponding level and adjust the dosing pump if needed. The dosing pump is designed to deliver the effluent to the mound in small doses over time, so the mound can handle the load. Monitoring ports can be added if they were never installed.
If the service company cannot fix the problem, you will need to investigate further. I would start by having the original system designer inspect the mound system to confirm that it was built to their specifications. If not, then the installer is responsible to make the necessary corrections.
If necessary, you can bring in another soils engineer as an independent third party to analyze the cause of the failure and determine who is responsible. Your local health department, or whoever oversees septic system permitting in your area, may also be helpful in determining the cause of the problem and who is responsible.
Hopefully, your current system can be repaired or rehabilitated, and the responsible party will bear all or most of the cost. If you need a complete new system, you may need to get some help from a lawyer. You should not be on the hook for the cost of yet another mound system. In my region (northern New England) a mound system can cost upwards of $30,000.
Raj shah says
What’s Best Alternative Septic System for Commercial Site?
You have given really very detailed and important information. We just bought the commercial property on 1.2 acre land . The soil rest and available land based on the setbacks , conventional system is out of the way for usage considering 1500-2000 gpd . The Eljen system is also not big enough we can use . Is there a suggestion you can give and their maker and installer information for the state of Georgia if you would know. It is very crucial to find some system that would work until sewer comes near by – may be 2 to 5 years.
buildingadvisor says
Your best bet is to contact an experienced septic system design professional in your area. I would look for a sanitary engineer or civil engineer since it sounds like you will need a custom engineered system – not a boilerplate plan they can pull from a table.
Septic systems are a local affair. A local engineer will be familiar with the regional soil types, local regulations, and the folks who enforce them. They will also be familiar with the types of alternative systems that are acceptable in your area. If you need to push the envelope a bit with a novel approach, they can help you get it through the permitting process.
If you’re confident that you will only need the system for 2-5 years, then you will certainly want to go with the one with the lowest installation cost. For a longer-term system, annual maintenance costs and system longevity should get equal consideration.
There is such wide variety of manufactured and site-built alternatives systems out there that I cannot say which is right for your situation (I’m up in northern New England, where the go-to plan for most difficult sites is a mound.) Best of luck in finding a cost-effective solution!
Mike Gould says
Any Way To Build Over Existing Septic System?
I would like to add on to the back of my house. However my new addition would be covering up half of my septic tank and part of my drain field. I’m on a septic tank and not eligible to hook up to city sewer. I have 20 ft from my building to my property line. Unfortunately the drain field would be affected by adding the addition to my garage and master bedroom. Any suggestions on of what I could do differently would be appreciated. Thanks in advance, Mike
buildingadvisor says
All things septic are governed by local regulations, usually under the control of the health department at the town or county level, sometimes in accordance with state law. So you need to start your research there. (If you’re not sure who to talk to, your dept. of building inspection can point you in the right direction).
I’d suggest meeting with the local permitting authority to discuss your plans. Bring a site plan along with your new footprint marked out and ask what will be needed to proceed. There’s a good chance that you will need to start from scratch with a new perc test, new septic system design, and all new septic system components. Most towns require a clearance of 10-20 ft. from the building to any structure, even a deck or shed.
While it is possible to move a septic tank that’s in good condition, usually it makes more sense to install a new one. Concrete tanks are easily damaged when moved and metal tanks are rarely in good enough shape. If you no longer have space for a full-sized drain field with the required setbacks, you may need to get a variance regarding the setbacks.
If space is limited, sometimes you can use leach pits instead of a conventional horizontal drain field. There are other alternative technologies that can reduce the size of the drain field, but these tend to be expensive, more complicated, require more maintenance, and are subject to local acceptance.
As far as building on top of a septic tank and drain field, that presents other problems. Most likely, you will need to remove the old tank and refill the area with compacted granular fill. The same goes for the drain field. In general, any new foundation footing needs to be on undisturbed soil below the frost line – or on properly compacted fill. A slab also needs to be on a solid, well-compacted subgrade – not the case with a drain field.
This is probably not what you wanted to hear, but I don’t know any way around it other than to redesign the addition so it does not intrude on your septic system.
Mark Jurgielewicz says
Alternatives to Low-Pressure-Dosing System?
Hi, Because of poor soil conditions, to build my house, I had to install a low pressure distribution system. Even with such, the house was only approved for two bedrooms. Is there another alternative system that would allow increased bedroom capacity with the same distribution area?
buildingadvisor says
Low-pressure-dosing systems (LPDs), like you have, are used to pump partially treated effluent into the drain field in controlled doses several times a day. LPDs and similar pumped systems are used to spread out the load over time to prevent overloading of the drain field. They are used when site conditions are not optimal for on-site sewage. This could be due to marginal soils or where there are only a few feet of good soil before hitting impermeable conditions.
In general, pressurized systems include one or more tanks or chambers to pre-treat the wastewater and a pump tank to hold the effluent before pumping to the leach field. Some systems use a typical one or two-chamber septic tank, while others may need additional treatment with an ATU (aerobic treatment unit). Another option for additional treatment is to place a sand filter between the dosing system and the drain field. This usually requires a second pumping station.
Finally the drain field, itself, may need to be a “mound system” if required by site conditions such as poor soils or a high water table.
Each deviation from a conventional gravity drain field increases the cost, complexity, and maintenance requirements of the system. At the high end, systems can cost two to three times the cost of conventional system with annual maintenance fees as well.
So it is possible that you can get a three-bedroom system on your lot, but at what cost? That’s the engineering side of the equation, which can be handled by an experienced septic system designer, who will be able to lay out the options and approximate costs. The other limiting factor is the regulatory system. What do they allow in your area? This varies widely from one jurisdiction to the next.
Anyone installing an alternative septic system should ask a lot of questions about the performance, longevity, maintenance requirements, and “care and feeding” of these systems as they are less robust than a conventional gravity system. If you are in rural area, what about power outages? Is a maintenance contract required and what are the annual costs?
Finally, stick with a system with a proven track record and skilled installers in your area. You don’t want to be a guinea pig for the latest innovation in waste treatment. The more complex the system, the greater the risk of costly complications down the line.
Dave Day says
Site Won’t Perc – Can I Use A PUmp-Out Tank?
Hello from the coast > I have inherited property that won’t perc but was wondering, why can’t I have a large, maybe 600 to700 gal. above-ground fiberglass, heavy duty tank, for a septic system and have the local honey wagon pump it out once a month. it would be fenced of course w/flowers and shrubbery, ect. ?
buildingadvisor says
It’s possible to use a sealed tank in this way, but the local authorities may not give you a building permit without an approved septic system. Also, with an above-ground tank, you would need to pump the sewage into the tank unless the house were uphill from the tank. An alternative septic system might be allowed, but these usually cost 50% to 100% more than a conventional system and also require more frequent pumping and maintenance.
If you do decide to store and pump the sewage, you may be able to dispose of the gray water separately to reduce the volume of sewage stored on site.
If you’re just planning to use the land for a camper or rustic cabin, you might be OK with a pump-out tank. However, if you are planning to build a house, I would consider the resale value, even if the town allows you to build. Not many people want to pump out their septic tank once or twice a month.
According to the USGS, the average US family uses 70-100 gallons of water per day for each person in a household. Even if you cut that in half by using water-conserving fixtures and separate disposal of gray water, you might find that you are pumping out your tank a lot more frequently than you envision. So you might need a much larger tank and can expect to spend $200-$300 each time you pump it.
Dave Day says
Steve.. Thank you for your timely and informative reply, You brought up about 10 things I hadn’t thought of, The house is on pilings but consumption/costs/esthetics outweigh the idea —back to square one. T thanks again, Dave
Linda Kerr says
Are Composting Toilets Allowed?
I want to build a small house on my land, which is heavily wooded except for the 25×40 spot where I want the house, and the (narrow) driveway accessing it. I don’t want to cut down any trees if at all possible. Also, the soil is very shallow, with granite less than 3′ below the soil surface, at the most. I would love to use a composting toilet and then just have a system for the graywater, and skip the traditional septic system, but I want to be sure I meet all local codes.
buildingadvisor says
Regulations regarding composting toilets vary from state to state, and the city/town/county health department may have its own rules that are more restrictive than the state law.
Some states allow composting toilets only if no other system will work. Some allow them as long as you have a conventional septic system for graywater. Some will only let you install a composting toilet if you already have a conventional system approved and in place.
With ledge at less than 3 ft. below grade, you would probably need a mound system or other alternative septic system to allow the required clearance to groundwater or impervious soil.
Most local jurisdictions will not issue a building permit without the health department first approving your on-site sewage system, so it is important that you get this squared away.
The laws can be pretty confusing and local authorities may not be very familiar with these systems. I would start by contacting the building department or health department in your local jurisdiction to find out what is required. Scheduling a face-to-face meeting can be helpful. If you have a specific system in mind, bring documentation of the system’s technology as well as all certifications from NSF (National Sanitation Foundation) and ANSI.
You can find a good overview of the regulations at this link.
MissPiggy says
Septic System That Works on Wetlands?
It was a great post and thank you for sharing your knowledge. I’m looking to purchase a land in North Carolina which only provides gas and electric for utilities. The property is a wetland and has no public sewer available. I plan to build a vacation home for my family and eventually my retirement home. And the only option I have is to put private septic tank for sewer. What would you recommend on the type of septic system I should put to a wetland property? Is the Alternative I tried looking for company who does alternative engineered septic system and can’t find any. Will you be able to direct me how to find them.
buildingadvisor says
The first question is whether you can or should build on a site that is wet and may be a legally protected wetland. In most places, you cannot get a building permit to build on a wetland. And even if you can, you need an expensive and sophisticated drainage and foundation waterproofing system to keep the home dry and free of ongoing moisture problems.
Building an alternative septic system on wetlands is perhaps a greater challenge. A conventional leach field cannot be used with a high water table. In some cases an aerobic treatment system or a recirculating sand filter can produce water that is clean enough to discharge to surface water after disinfectant is added. But getting permission for alternative septic systems requires the cooperation of local authorities, as well as septic designers and installers experienced with this type of system.
Also plan on much higher costs to install and maintain such high-performance systems, some of which operate like a mini sewage-treatment plant. Plan on more frequent pumpinp and regular monitoring, often handled throgh a maintenance contract.
What types of alternative systems are allowed depends on local regulations and the discretion of local officials. Definitely meet with them (building or health department) to review your options before proceeding. They can also give you the names of licensed septic system designers in your area. Often these are civil or soils engineers. Find someone who has designed successful systems on similar building sites.
I would not purchase this type of land without written confirmation from the local authorities that you can build a house and septic system on this property. Make any offer to purchase the land contingent upon the necessary approvals – or you could end up with a unbuildable and virtually worthless piece of land.
Best of luck with finding a suitable lot!
David says
Septic System Options With Compressed Soil?
A soil engineer determined my lot to be unsuitable for a septic system due to soil compaction that occurred over the years caused by poor farming techniques. Most the topsoil has also been eroded from the top of the hill we planned to build on.
What are my options if a traditional septic and/or mound have been rejected?
buildingadvisor says
There are three main issues to consider:
• What will work effectively?
• How much will it cost to install and maintain?
• What will the local authorities permit?
There are systems that can deliver water clean enough to discharge to surface water, such as an Aerobic Treatment System, which you can read about at this link. Many of these systems use fan-forced air, in addition to dosing pumps, and some add a disinfectant as the final treatment step before discharging the wastewater. Think of this a mini-wastewater plant, with some of the same maintenance requirements.
A recirculating sand filter is a similar system with a few less moving parts (no fan-forced air).
Both of these systems are expensive to design and install and require more monitoring and maintenance than a conventional system. There are many design variations and each system needs to be carefully engineered. As a practical matter, the more pumps, fans, and controls, the more there is to go wrong.
On rural sites with a large area for disposal, you might want to consider drip irrigation or even a constructed wetland. These are conceptually simpler, but require more active involvement than most people want with their sewage.
As for what the local authorities will allow, this varies all over the map. It often takes some negotiation to get permission to install a system that is not widely used in your area. Your best resource is often a local engineer or licensed septic system designer who is familiar with the local regulations and the people who enforce them. They can help you find the most cost-effective solution that will get approved.
Dave says
Steve,
Thank you. This is very helpful and at the very least, gives me a glimpse of hope.
When you say “discharge to surface water” does that mean water discharged into another body of water such as a pond or creek? Or does it hit the surface of land?
Dave
buildingadvisor says
Around here, in northern Vermont, I know of several aerobic treatment systems (also called aerobic treatment units or ATUs) at lakeside vacation homes. They systems are within, say, 100 feet of a large lake, so the discharge ends up in the lake sooner or later. Depending on the system design and local regulations, these systems may discharge to gravel trenches, be dispersed over a large area with spray nozzles, or discharge directly into a stream or lake after being disinfected – depending on local regulations.
Discharge to open water is probably not a great idea in the event that the system is not working 100% as planned. Nitrates may be removed, but harmful bacteria may still be present. Also the discharge from these systems can have a noticeable odor. Good engineering, careful construction, and proper maintenance are critical for success.
For more information, view Aerobic Treatment Units, published by the National Environmental Services Center (NEFC).
Best of luck!
Jim says
Why Mound Requires Undisturbed Soil?
My lot was perc tested in the front part and requires a mound system. I would prefer the system in the back of my lot, but my contractor says it had been disturbed when they developed the subdivision. Why can’t a mound system be on top of “disturbed” ground?
Its been apprx 15 years since the ground was “disturbed”
buildingadvisor says
Placing the drain field (leach field) on “undisturbed soil” is a standard specification for conventional septic systems and many alternative systems, such as mounds. The assumption is that the soil under and around the drain field will absorb, filter, and provide the final treatment of the effluent as it flows through the gravel trenches of the drain field. The soil must be permeable enough to accept the liquid, but fine enough to filter out the remaining bacteria before the water returns to the aquifer.
Soil that has been compacted by traffic, regrading, or filling will generally not perform as well as undisturbed soil that meets the criteria for a drain field, as determined by a perc test and visual classification of the soil in an observation hole. The permeability of the soil as measured by the perc test results determines the size of drain field. In a situation like yours, it is also difficult for authorities to determine what areas are disturbed and which are natural. To make their lives easier, they stick to the undisturbed soil rule.
At what point is soil considered “undisturbed” for purposes of placing a drain field? Ten years? Thirty years? One hundred years? That’s really up to the health department of whoever issues the permit for the septic system. Engineers and septic system designers apply a large safety factor in their calculations and don’t like unknowns.
On occasion, people try to pass a perc test by adding a thick layer of permeable soil removing and replacing poor soil with more permeable soil – something frowned upon by the local authorities. On the other hand, since your mound system is presumably an engineered system, maybe the engineer can come up with a suitable design that the local authorities will accept. If a mound system won’t work, ask what other alternative systems might be acceptable.
Having a site that does not perc can be costly and frustrating, but sometimes the local authorities will work with you to figure out a workable solution.
See also: Perc Testing How a Septic System Works
John Vogler says
As a follow up to this discussion, I own a vacant lot next to our residence and may one day want to build upon it, likely needing a mound system. I would like to maintain the lot until that time comes and develop lawn on the lot. Would I be runninng the risk of causing future problems by creating disturbed soil and no longer having the needed undisturbed soil for the system? Is it better to just leave the area alone?
buildingadvisor says
The short answer is, yes, it’s better to leave the area alone. While planting a lawn should not, by itself, disqualify an area from future use as a leach field, it raises the question of to what extent the soil has been modified. Any excavation, regrading, or compaction of the soil (from traffic or equipment, for example) could cause problems.
Once the drain field or mound has been created, a simple lawn above is the preferred landscaping.
The general trend is toward more stringent septic regulations, so why do anything that potentially complicates the testing and approval process? It may make sense to complete the soil and perc testing sooner rather than later, depending on your building plans and the time limit on test results. Once you have established your house site and drain field area, you can start tinkering with landscape in a way that’s consistent with your building plans.
Mike says
Can We Temporarily Use a Holding Tank?
Hi. The builder has completed our new home we are 13 days out from settlement. However the Health Department will not pass the spot where the sand mound is going because the land is to wet. Is there an alternative system or another alternative to get us in the home until they can build the mound?
buildingadvisor says
There may be some options from a technical perspective, but the bigger concerns are whether they would be cost-effective or acceptable to the local authorities.
The mound system you have planned is usually the cheapest “alternative” system on a marginal site that cannot pass a standard perc test. Designing and building another alternative system for temporary use – assuming you could get it approved – could add $15,000 to $20,000 or more to your budget. Also, any system that discharges the effluent to the soil would probably be vetoed by the health department if the main problem is wet soil or a high seasonal water table.
If it’s allowed, your cheapest option would probably be a holding tank that is pumped out regularly. A holding tank is a steel or plastic tank with no outlet. It simply stores the wastewater until it can be pumped and treated somewhere else. It’s a larger version of what you would find on a boat or large camper. Holding tanks typically have a high-water alarm to let you know if the system is full. Weekly or monthly pumping would be require depending on the size of the tank and usage level.
Hope you’re able to work something out with the health department. Best of luck with your new home!
Mike says
Thank you so much so. If we went with a 1000 or 1500 gallon tank with 5 adults, what’s your guess of how often it would need pumped ? When ground dries they can put mound in.. thanks mike
buildingadvisor says
The average American uses 70 to 100 gallons of water per day. Septic system designers generally use a rate of 150 gallons per day per bedroom – based on 75 gallons each for two people. With low-flow fixtures and water-conserving practices, you may be able to cut that to 40-50 gallons per day per person.
The biggest uses are toilets, followed by showering and bathing.
So with five adults, you will be probably be pumping the system weekly with a 1,500 gallon tank unless you can cut down dramatically on water usage.
Best of luck!
doug says
Septic System for Clay Soil?
Hello. Can I put a conventional septic system under a layer of clay?
buildingadvisor says
The short answer is to get a perc test, and if the lot passes, a septic system design will specify a leach field that will work. A marginal site will require a larger leach field, but otherwise should work fine as long as the installer follows the plan. For example, backfilling with dense clay soils to save money could undermine the system’s effectiveness and shorten its service life.
Drainage from a leach field is downward and sideways, so the type of soil above is less of a concern than the soil below. However a thick layer of very dense clay soil on top could potentially prevent air from reaching the bacteria that a leach field relies on to treat the effluent. Aerobic bacteria in the leach field require adequate contact with air to function properly.
If your site has a shallow layer of clay with well-draining soils below, you might be OK. However if the clay runs deep enough to impair the drainage around the gravel trenches, then you will probably need to use a mound system or other alternative approach.
Generally, the leach field pipes are buried about 18 to 36 inches below grade. The pipes are embedded and covered in granular fill, but the top layer of backfill, about 6-12 inches deep, is typically native soil or topsoil to support a lawn. Moderate clay content in this top layer should not be a problem unless the layer is deep and dense enough to starve the leach field of oxygen.
Best of luck with your building project!
John unruh says
Best System for Clay Soil, High Water Table
I live in Salisbury MD and have a failed leach field. Wicomico County came out and said we have a high water table. (We had inch of rain the day before). The home was built in the 70’s. The inspector said the homes on my road should never have been built because of the clay. They haven’t decided on what system yet. Wondered what options are best for me and to not get railroaded by the county. The previous owner built a screened-in porch over septic tank.
buildingadvisor says
Where I live in northern New England, we have a lot of heavy clay soil that does not perc. The most common and cheapest alternative here is the mound system, which can also be used with high water tables. So it should address both your problems.
Essentially, a mound system is a raised leach field with an extra component called the “dosing chamber”. The dosing chamber is an additional smaller tank with a pump that sends controlled amounts of effluent to the raised leach field. This ensures that the effluent is well-distributed in the field and pumped at a manageable rate. The pump is usually controlled by a float system with a high-water alarm that signals a problem with the pump.
Mound systems can cost twice as much as conventional systems, create large hump in your landscaping, and require a lot more maintenance and inspections than conventional systems. On the other hand, they work well and allow you to build on otherwise unbuildable sites. Some municipalities require that homeowners contract with a maintenance company for upkeep, an additional expense. Unless you are handy and want hands-on involvement with your septic system, this is not a bad idea as regular maintenance is needed for the system to perform properly and provide a long service life.
You can find a good overview of mound systems at this link.
Amie says
Septic Systems Near Chesapeake Bay
Hi there. I live in Parsonburg Maryland. I was wondering what type of septic system the city has you install?
buildingadvisor says
If you are within 1,000 ft. of the Chesapeake Bay, you may be required to install an engineered septic system designed to reduce nitrogen levels beyond the treatment levels of a conventional system. These nitrogen-reducing systems are referred to by the state of Maryland as BAT (Best Available Technology) units. BAT units are manufactured systems approved by the state to pre-treat effluent in combination with the septic tank.
The nitrogen-reducing units have electrical and mechanical components which need periodic maintenance. Many people purchase a service contract to make sure the work is done properly and on schedule.
Maryland’s regulations regarding BAT systems changed in 2016, and county regulations may be more restrictive than the state’s. So it’s always best to check with a representative of the local health department before getting to far along in your building plans. Maryland also has programs in place to pay for some or all of the added cost of these systems.
You can find more information about Maryland’s state and country septic system regulations at this link.
Kim says
County Will Not Allow Us to Replace a Failed Septic System
I am currently selling my home that was purchased two years ago. When the home was purchased, the septic system passed no problem. We recently had a contract on our house and it failed septic inspection this time around. I went to the local health department and filled out the paperwork for the county to install a new environmentally friendly system as we are in the critical area of the Chesapeake bay. A septic inspector told us that the water table is too high and that is why our septic system had failed. I located the records from the previous owners of our house in the meantime and found that the septic system was most recently installed in 2005 and was approved by the local health department. When the county came to do our perc test two weeks ago, they deemed our land not viable for any septic system and said that our only option is a holding tank. My question is how can our land not perc or not be suitable for any system at all when it was just approved and installed last in 2005? I do not understand how this is possible.
buildingadvisor says
Sorry for your situation – sounds like a tough one. It’s quite possible that the laws are being enforced more strictly on you than on the previous owner. This is unfair but not uncommon.
In an environmentally critical area like yours, county or state rules may preempt local regulations. It may also be that local and/or state rules have changed since the system was installed in 2005. The stricter current rules are sometimes triggered when a property is renovated or changes hands. At that point, the government has the leverage to say update your system now or we won’t allow a sale or issue a building permit.
Unless a change of law occurred in the past two years, it is unclear why the previous owner did not face the same problem when selling the property to you. It’s possible that they slipped through the cracks as land use regulations are not always consistently enforced. Perhaps the seasonal water table was lower at the time of the last inspection and the system squeaked by.
There are a number of issues to consider. One is whether your system is actually failing and polluting the groundwater. If it is, then the next question is whether there are any alternative systems that could work successfully — there are solutions that can work on almost any site, but the cost can be prohibitive. The next question is whether you could get such a system approved by the local health department. Then the big question is can you afford it?
In many cases, local governments will work with homeowners to find a workable solution if their septic system was installed legally and properly under an older set of regulations. It does not sound like the county inspectors expressed such flexibility in your case.
If I were in this situation, I would find out who is the controlling authority (town, county, state) and schedule a meeting with the highest level person I could wrangle a meeting with. Bring as much documentation as you can about when the current system was installed, how and why it was recently tested, and why it failed this time. Ask what options you have to avoid the significant economic loss from selling a home with no functioning septic system.
In some waterfront locations, regulators allow aerobic treatment systems, technically not a septic system, but one that can purify effluent to a degree that it is suitable for release into open water.
If you run up against a brick wall, your next stop might be a good real estate lawyer familiar with septic regulations in your area. They may have some ideas beyond those being offered by the local authorities.
Kim says
Thanks so much for the response and useful information. Will this significantly affect the sale of our home? It is a small cottage (1200 sq ft) on the water with two bathrooms.
buildingadvisor says
Put yourself in the shoes of the buyer. Would you want to buy a cottage with a failed septic system and no solution other than a holding tank, which would need frequent pumping? These are issues that you would be legally obligated to disclose to the buyer. Also, you will probably have to have some type of functioning system in place prior to selling.
The lack of any legal options for on-site sewage treatment would definitely reduce the property value, but I can’t say by how much. A real estate agent or real estate appraiser could give you a better idea.
Hope you can work out a solution acceptable to the local government. There is almost always a workable solution if they are will to be open-minded.
Paul Julian says
Not sure of the county or state where you are located, but in Virginia, alternative Drainfields or direct discharge (after treatment) are acceptable and are most often seen athe coast at Va. Beach or Eastern Shore.
Ron says
I feel your pain, Kim. I’m in the critical area of the Chesapeake also (St. Mary’s County, MD). I applied for a BRF grant 3 years ago to upgrade my system prior to listing it for sale. Even tho there was no evidence of failure (standing water, back up of drains) the county failed my existing field (????), but said I could install a drip dispersal system. Problem is, all the contractors I’ve contacted either don’t even give me a price or jack it up to essentially take the grant money for themselves. In essence, they’ve highjacked a state program designed to help homeowners do the right thing.
Ric says
I am actually in the opposite position you are in. Currently I am looking at a house built in the 1950’s that originally had an outhouse. Sometime between the late ’60’s and early ’80’s a septic system and bathroom were added to the house. Because of the ruralness of my county at the time it’s questionable as to whether it was even permitted and definitely does NOT pass now. The last septic inspection showed that the land cannot even have a drainfield on it at all. The owner (not me) was told he basically has a lot for grazing with a really nice shed (the house is 2br/1ba). Lucky for him I really like the property and location and I am looking into alternative solutions. Unluckily for him this has dropped the price to little over land value. I feel for your situation. There are many alternatives but they are not inexpensive. and I am still doing my research. I am a research hound when it comes to high dollar long term investments especially real estate. When I find a solution I will be more than happy to share it with you. I hope you will do the same. Maybe between the two of us we can come up with something to help. By the way, I am in Virginia if that helps at all.
pat says
Welcome to the game! As long as you don’t have a backed up leach field, or smells and odors, you won’t have any problems. The minute you do have a problem though you need to spend $20K on a new environmentally approved alternative “mound” system in a lot of states and areas. Unless the code enforcement is breathing down your neck like in most cities and large towns, you may be able to just get two 1,000 gallon tanks and just pump them out yearly. Seems to me like if your system was approved, it should be grandfathered if an engineer signs off on some repairs. Or you could try and see what you could get away with.
Ms. Pereaga says
Perc Tests Needed for Composting Toilet?
Do I still need a perk test if I am only doing a composting toilet and not using a septic tank?
buildingadvisor says
Composting toilets are currently allowed in dozen or so states under certain conditions, subject to approval by the local health department. Each state and local jurisdiction (town, city, or county) has its own regulations in compliance with state laws. In some states, lots over a certain size – say, ten acres – only need to comply with state law, which may be more flexible on septic system regulations.
Some of the states that allow composting toilets include Arkansas, Colorado, Florida, Idaho, Illinois, Maine, Massachusetts, Oregon, Pennsylvania, S. Carolina, and Tennessee. Some states prohibit them, and many have no regulations at all on composting toilets, meaning that you may be able to use them if you can get permission from local authorities. Some jurisdictions have the authority to approve “experimental and innovative” wastewater treatment systems on a case-by-case basis.
In states that so allow composting toilets, rules vary a great deal from one state to the next. Some states do, in fact, require a perc test to insure that a conventional septic system could be installed in the future. Most states that allow composting toilets require an approved system for managing greywater, that is, water used for washing and bathing. In addition, some state require that the composting toilet be NSF-certified, manufactured products – not site-built.
When in doubt, it’s always best to check with your local health department as they make and enforce the rules for on-site sewage treatment. Best of luck!
You can find a good primer on composting toilets and other alternative system at this link.
Donna Zullinger says
Buying House After Failed Perc Test
I was looking at a house for sale. It was built in 1994 but it says land doesn’t perc. Didn’t it perc before they built it? Now what can be done? Thanks
buildingadvisor says
There are many possible explanations for how a house got built on land that does not perc under current regulations. However, this is a very big red flag.
Unless there is a municipal sewage system to tie into, you might need to construct an expensive alternative system if it’s allowed, or the house may be legally uninhabitable. Since there is already a house on the site, the municipal government might work with you to help find a solution, but there are no guarantees.
If you wish to pursue this further, contact the local (city/town/county) department of health or building inspection to find out what options might exist for this property. If the perc test results are on file, you can get the name of the firm that conducted the tests and contact them as well. They may be able to suggest alternative sites on the land to test or other strategies to pursue. Each town and state has different regulations and practices, so you need to pursue this at the local level.
If an alternative system is allowed by the local government, you can contact a couple of septic system designers in your area to get a better sense of the options and costs. Alternative systems have much higher initial costs and maintenance costs, so don’t jump into this without doing the necessary research.
gayle taylor says
Alternative Septic System for Clay Soil
About 50 yrs. ago I purchased 7.5 acres of land..now I want to put a house on it, but the land has clay soil and will not perc. Can you suggest a septic system that will possibly be used on this land? If possible I would like to get an estimate of what it would cost. I realize that it has to be approved by the state or the county, i think. Any help i can get will be appreciated. Thank you very much.
buildingadvisor says
I live in an area (northern Vermont) with a lot of clay soils. The most common, and least expensive, alternative system in our area is the “mound system” — essentially a raised leach field that creates an elongated mound in the yard alongside the home, combined with a “dosing chamber”. The dosing chamber is a second, smaller tank with a pump that sends controlled doses of effluent to the leach field. This provides for good distribution and manageable loads that the leach field can handle properly.
The cost of a mound system varies with the size of the system (how many bedrooms), soil conditions, type of pump and controls, local costs of sand and gravel, and regional construction costs. In this part of the country, mound systems often cost $20,000 or more. Annual maintenance can be $300 to $500, including more frequent pumping.
There are a wide range of alternative systems, but you need to find one that is acceptable to local authorities. Also, you should choose a system with a strong track record in your area and an experienced installer. I would steer clear of innovative systems that haven’t yet proven themselves in the field in your area. A failed system can be a costly and unpleasant mess.
Local septic system designers and installers can be a good source of information about what has been used successfully in your area. Also schedule a meeting with your local department of health (or building inspection), which oversees septic permitting in most areas.
Best of luck in finding a cost-effective solution!
Sean H says
Aerobic Treatment System for Waterfront Site?
I am looking at purchasing a waterfront lot in the Chesapeake Bay watershed. I am in the feasibility study period. It is mostly considered wetlands, but the Army Corps of Engineers has deemed an area as dryland suitable for construction. The land has perced for alternative septic systems. Because of the wetland resource protection area setbacks, I am further limited for space for a drainage field. As an order of magnitude ballpark estimate, how much area is needed for a 3 bed/2 bath septic field? What system would require the least amount of space?
Secondly, I really like the idea of the aerobic treatment system if it fits. I recognize there is more cost here and yearly costs for upkeep. But please explain what happens to the effluent in these cases. I have seen online what look to be prepackaged systems that seem to show the effluent getting sprayed, I assume as irrigation. They, however, recommend not doing this near pets or vegetable gardens. This idea seems like a non-starter. The image on this website shows an above ground gravel bed in a pressure treated wooden box. Is this for effluent disposal? Is the effluent supposed to evaporate? Please explain further.
buildingadvisor says
This is a complex topic with a lot of options. Each system has to be engineered to work with local conditions and local regulations. There are a lot of companies selling manufactured components and packaged systems. But separating the hype from proven real-world performance is tricky. Also regulators are reluctant to approve new systems without an established track record in their area.
I would only trust a licensed designer, preferably an engineer, with a lot of experience with the specific type of system you are considering. In essence, you a building a mini sewage-treatment plant which needs a lot more monitoring and maintenance than a conventional passive system.
On the plus side, the effluent is a lot cleaner than from a conventional system and can be discharged near open water or, in some case, sprayed above ground for irrigation, as you mentioned. Direct discharge often requires disinfectant to be added before the effluent is discharged.
The aerobic system pictured on this page (see photo) was installed recently on a waterfront home. The raised gravel bed functions as the leach field – roughly half the size of a conventional field. For a three-bedroom system (designed for up to six occupants) that would be about 200-300 sq. ft. The one pictured is about 10 ft. x 20 ft. FYI, the pressure-treated timber box in this system was not properly built and started to come apart at the corners, so reinforcement and cross pieces were added later as reinforcement. I learned this from a friend who lives next door. The neighbor has also noticed some mild odors at times, something to consider with any above-ground system.
With any active system like this, you have pumps, blowers, valves, electrical connections, and alarms to maintain – and possibly chemicals to add. Most owners, or HOAs for a community system, contract with a company to maintain the system. One reason that municipalities shy away from this type of system is that they fail rapidly when not properly maintained. You can read a good article on the topic at this link.
Brian says
Alternative System Denied Approval
I recently purchased a five-acre parcel knowing that it failed a perc test and had a high water table. I was told I could appeal, so I searched for options to overcome the obstacles, and the one I ended up proposing (based on feedback from a variety of local excavators) was to simply bring in a lot of fill dirt and sand in order to keep the drainfield 6-8 feet above the original grade (which is mainly clay). We felt confident in this proposal because it was the same process used on the neighboring property.
We didn’t find out until the hearing, however, that the other parcel had more sand in the soil, and our county prefers/requires a certain type of soil, even if that soil is partially removed and then covered up with 6-8 feet of approved sand. I doubt I can change the minds of the county, but it is frustrating because all of the excavators I talked to said this method provides a perfectly safe drainfield, even if the soil far below is clay.
Can you comment on this and/or direct me to resources the confirm our proposal? If we can find enough evidence that enough fill sand over clay soil offers an acceptable environment for a safe septic system, we can potentially change their mind. The next option otherwise would be an advanced system. Any recommendations on inexpensive options that would reduce/eliminate the need for a drainfield?
buildingadvisor says
Sounds like you are dealing with two issues – poorly draining clay soil and a high water table.
We have a lot of clay soil in our area and the most common solution, and least expensive, is a mound system. Because you are raising the level of the leach field with substitute soils, this helps with both the soil problems and the water table. In most cases these systems have an additional dosing chamber and pump to control the flow of effluent to the drain field. In theory, this provides better control and treatment of the effluent. With the added fill, extra tank, pump and alarm system, these are not cheap systems, but usually cheaper than other approaches. Also, they are a proven solution where the variables and performance is well understood.
Another option to consider is an aerobic treatment system, commonly used near surface water because of the high quality of the effluent. Like a mound, this is an above-grade system, usually housed in a bed of sand and gravel enclosed by heavy landscape timbers. The downside is even more moving parts (pumps and blowers) to keep it operating. You can read about this and other alternative systems here.
In my experience, most towns will not go for the solution you describe whether or not it will work. If the native soils do not drain well or you have a high water table, then they want an engineered solution such as a mound system.
As a practical matter, it seems to me that the best strategy is to bring a plan designed and stamped by a licensed septic system designer or sanitary engineer who does a lot of business in the town or county where you are building. They will know what will fly in your area and what type of evidence will persuade the local officials. These folks work together on a regular basis, know each other, and know the ropes. There are so many options and without this type of guidance you are shooting in the dark.
Municipal governments don’t like to take risks on building plans – septic, structural, or whatever – that are outside their normal standards and comfort zone. In that case, they want a suitable professional to take responsibility (and potential liability) for the nonstandard construction.
Since you probably don’t want to pay for a full plan at this point, ask the system designer for a feasibility study that you can take to the local dept. of health or whoever regulates on-site sewage in your area.
A professional might also provide you with a greater level of comfort that the system will work as planned. An underperforming or failed septic system is not a pretty sight and can be very costly to make right.
Best of luck with your local health department, who can also be a good resource for telling you what types of systems they might approve. In general, I’ve found town officials to be pretty helpful about regulatory issues if you approach them respectfully, explain what you are trying to do, and ask for their advice. They usually appreciate being consulted ahead of time.
Tiffany says
Subsidies for Alternative Septic Systems
We just bought land in northern New Mexico (Rio Arriba County) and, now, we are afraid that it won’t pass the perc test. Our neighbors have septic systems, but one is unpermitted and appears to be backing up and I think that it may be due to the soil.
Alternate septic systems sound expensive; are you aware of any programs that help offset the cost?
buildingadvisor says
Until you do a perc test, or at least consult with a soils expert familiar with local soil types, you won’t really know where you stand.
Your neighbor’s unpermitted system may be backing up due to poor soils, a high water table, or a poorly designed or poorly maintained system. The perc test and soil observation (deep hole test) are used not only for permitting, but to design a well-functioning system.
Some states and towns do have programs that provide grants or low-cost loans to replace failed septic systems or install new ones — especially in environmentally sensitive areas such as the Chesapeake Bay. I would start by contacting the local jurisdiction that oversees septic permits – typically the town or county health or sanitation dept. to find out what testing is required, who is allowed to perform it, and what types of alternative systems are acceptable. You can also ask them about possible sources of financial assistance.
Best of luck in finding a cost-effective way to develop your land.
Tom McConaghie says
Site Perced Before, Failed Now
About 40 years ago I bought a lot in a trailer park called Sea Village located in Brunswick County, NC with the plan of retiring there. At the time, the property perced, however; now that I’m retired, it has since failed 2 perc tests. It’s a sandy soil with a high water content. Can you recommend a system or steer me in the right direction that will satisfy the perc requirements?
buildingadvisor says
Sorry to hear about your situation. A failed perc test is never good news.
In general, sandy soils drain well unless it is very fine sand. In fact, some course sand soils perc so fast that the effluent can pollute the aquifer if the system is not properly designed. However, if the soil on your site is saturated due to a high water table, then it will fail no matter what the soil type. Perhaps development in the surrounding area over the years has changed the drainage characteristics of your building site, making it wetter.
There are a variety of alternative systems that may work on your site. The most common alternative is the mound system, which can be used on sites with high water tables. Check with your local health department to find out what types of alternative systems are allowed in your area. Then you would need to consult with a sanitary engineer or soil scientist to find out what options would work for your site. In some cases, you may be able to tie into a municipal or community system.
Alternative septic systems are more expensive than conventional systems and generally have higher maintenance costs as well. Most have pumps and an alarm that sounds if the pump fails. Some of the more innovative systems have not been around long enough to have established engineering standards and a track record, so towns may be reluctant to approve them. Before making a choice, make sure you understand the costs and risks involved in an alternative system as a failed system is unpleasant to live with and a potential health hazard.
I hope you are able to find a workable solution for your site. If you are unable to build, or it is too expensive, it may be possible to sell the lot to a neighbor who wants the land as a buffer or to enlarge their yard area. Best of luck!
Our sister site, Inspectapedia.com has has a lot of good information on alternative septic systems.
Nate says
Constructed Wetlands in Cold Climate?
Aloha,
My wife and I currently live in Honolulu, but we are planning to buy some property in the San Bernardino Mountains (California) and build a house there. We’ve been told that the property we have our eye on has had percolation problems, but there hasn’t been a perc test in 15 years.
If it is impossible to create a working septic system, we simply can’t buy the property and build. However, if there’s a way to build an alternative system even if the perc tests aren’t good, then we’d definitely want to buy this. (The land is flat, and the houses in the neighborhood all apparently have working septic systems.)
Any help or advice you can provide would be helpful. I’m really interested in the idea of a constructed wetlands, but I don’t know if that would work in a place where it gets cold enough to snow several months of the year (it’s Southern California, but it’s at 6000 feet).
Mahalo!
buildingadvisor says
Your options for an alternative septic system are determined by both technical and regulatory issues. Each local building jurisdiction (town, city, or county, and some states) has its own rules about what types of alterntive systems are allowed and under what conditions.
Your first step should be to contact the department of health or sanitation where the lot is located to find out what is allowed on this site and under what conditions.
If it sounds at all promising, you’ll need have a new perc test conducted as the results are typically valid for only 1-3 years. If the site has failed in the past, chances are it will fail again, but you may find a portion of the site with better soil conditions. It’s best to make any offer to purchase the land contingent on a successful perc test.
If the site does not meet the requirements of a conventional system, the most common alternative is a “mound” system, where suitable soils are brought in and placed on top of existing soils creating a mound. These usually require a pump and monitoring/alarm system and can be double the cost of a conventional system. A big factor in the cost is the price of sand and granular fill (crushed stone or gravel) in your area.
There are a variety of other options, including manufactured leach fields, drip irrigation, and constructed wetlands. I only have experience with mound systems, which are very common where I live as we have a lot of dense, clay soils in my area with very poor drainage.
I know of a couple of constructed wetlands in rural areas with less restrictive building codes. These require a fairly large area and can be designed for either surface flow or subsurface flow. Surface systems have more issues with odors and may have performance problems with freezing temperatures. These systems are uncommon and must be built and maintained correctly to function properly. So finding a designer with many successful systems under his belt is essential unless you want to be a guinea pig for an experimental system.
Read more at this link.
Best of luck with your building plans!
Ellen says
What Site Conditions OK for Drip-Irrigation System?
My question is whether Alcovy and Santuc are drier soils, which would allow for a drip-irrigation septic system vs. more moist soils? If a lot does not perc, does the soil scientist take into consideration that heavy rains that may be coming, and the water that should be flowing through the culvert pipe across the street, but doesn’t because the pipe is broken? Also is the flow of a natural spring-fed stream taken into account? What if it’s a drought when soil testing is done? Does the soil scientist still have to consider the other mentioned items above?
buildingadvisor says
Alcovy and Santuc “soils series” which are large groups of related soils, so it’s hard to say whether yours will perc without testing. In general, these are moderately well-drained soils, so there’s a good chance they will perc.
Weather conditions do effect perc tests, which measure how fast water drains though the soil indicating how well it can treat sewage. For example, in very dry weather, water may drain faster than normal. Therefore, many towns specify what time of year a test can be done – typically during the winter or spring when soil is more saturated (but not when soil is frozen). Allowable times may vary from year to year, or during unusually wet or dry weather.
Most towns also require a “deep hole” test to observe the soil layers and determine the seasonal height of the water table, which must be safely below the leach field.
If a lot does not perc, then the locations of culverts, streams, and other surface water won’t help you. However, they would limit where you could build as the septic system must be a certain distance from streams and other surface water.
You can hire a soil scientist to do a quick analysis before you invest in a full perc test and deep hole test.
Gayle says
Who Pays For Perc Test?
When purchasing land, who pays for the testing, seller or buyer (normally)
buildingadvisor says
Who hires the tester and pays for the test is negotiable like most things in a real estate transaction. In an improved lot, the test has usually been completed before the land is offered for sale. In this case, the buyer needs to confirm that the test was done properly and that the results are recent enough that they are still valid. The town building, zoning, or health department should be able to provide that information.
If the lot is unimproved, who pays is negotiable. From my perspective, it’s best is for the buyer to hire the tester and pay for the test so that he gets the full results and any relevant information about the soil and drainage conditions. If possible, write the offer with a contingency that requires the seller to pay if the test fails. You can factor the cost of the test, if successful, into your offer amount.
mel says
Self-Composting Toilet For Failed Perc Test
I read about the Failed Perc test solutions and did not find any reference to one of the most easily installed, extremely cost effective and most simple solution — its called the Self Composting Toilet. This toilet is an all in one unit — check out Sun-Mar or Envirolet for more details. I had bought one way back in the early 70’s and used it at our cottage, for a family of 5 it was absolutely excellent, cheap (they sell for approx $1000 and up. If the perk test is negative and you want to dig your yard out and add mucho shale, gravel etc etc it would cost in the range of tens of thousands of dollars while a composting toilet is environmentally friendly – cost effective and self contained. check it out mel
Weber says
In some states no septic system equals not being allowed to have running water on the site. For instance, in Tennessee if you can’t fit a septic system on a lot without sewer access you are not allowed to have running water on that property. Graywater must go through a septic system before being released into the surrounding environment.