In This Article
Aquifers
Siting a Well
Dug Wells
Driven Wells
Drilled Wells View all WATER WELL articles
Wells can vary a great deal in depth required, flow rate, and water quality. Before buying a lot with a well in place, you should get the reported flow rate in writing and an up-to-date water quality report, readily available from most municipal health departments. Ask the local health inspector about their water testing procedures, which are usually inexpensive and well worth the cost and effort. If problems are detected with the water quality, these need to be identified and resolved before proceeding.
Also pay attention to the flow rate. While a good flow rate today does not guarantee a good flow rate in other seasons, an experienced local well driller should be able to give you a good idea about the flow characteristics of wells in your vicinity and alert you to any potential problems.
If there is no well in place, you should talk to at least two well drillers in the area, as well as neighbors, about well depths, flow rates, and water quality in the area. Get both the hands-0n prospective of local well drillers and the more scientific opinions of geologists and hydrologists.
The state or local office of water resources or geology may also be able to assist you with water maps and other information about available groundwater. Another place to look for help is a Cooperative Extension or School of Agriculture at a local university, which probably employs one or more hydrologists, who study water resources for a living. They can provide a good indication of whether and how you will be able to meet your water needs.
For example, if you need a lot more water than your nearest neighbors, you may need to drill deeper or drill more than one well. If a very deep well is needed, you will need to budget accordingly. However, well drilling is based on an educated guess of underground conditions — there are no guarantees.
If you do not yet own the land, and the availability of adequate water is in question, you may want to make your bid contingent upon drilling a test well of sufficient flow rate and water quality. This will cost you few thousand dollars, but could save you many thousands more.
AQUIFERS
Aquifers are natural areas of water storage under the ground. While many people think of aquifers as underground pools, they typically consist of areas of permeable sand
and gravel , and cracks in solid rock where water is able to slowly flow. How much water the rock and granular soil can hold depends on how much open space exists between the particles, called its porosity. This ranges from 0 in solid rock to about 30 or 40 percent in gravel and sand.
Aquifers have a bottom, where the soil or rock is impermeable, and a top, called the water table. The water table may rise to the surface of the earth at a natural spring, or at a pond or lake, but usually it is well below the surface.
Water tables can be a few feet thick or hundreds of feet from top to bottom and can range in area from the size of a pond to hundreds of miles across. Aquifers are replenished primarily by rainwater that percolates through the soil.
Unconfined vs. Confined Aquifers. In an unconfined aquifer, the top of the aquifer is the water table and the water must be pumped upward (see Illustration). If an aquifer is confined between bedrock and another layer of impermeable material, such as clay, the water may be under pressure and rise above the aquifer when drilled into. In some cases, the water will rise all the way to surface without a pump, creating an artesian well.
To reach the aquifer, you may need to drill 30 feet or 500 feet. Aquifers tend to follow the slope of the land above and water tends to move slowly through the aquifer following the slope. The rate of flow depends largely on the permeability of the rock and other material in the aquifer. When water is pumped from the aquifer by a well, it is drawn down in a area around the well. The more permeable the material in the aquifer around the well, the faster the well area will be replenished and the greater the well’s flow rate.
Depending on the geology, there may be and adequate supply of pure water relatively near the surface, or you may need to drill into deep water-bearing rock to get adequate flow and flow. Based on their knowledge of local conditions, an experienced well driller or hydrologist can help determine the best strategy.
SITING A WELL – WHERE TO DRILL
A knowledgeable well driller, or if necessary, a hydrogeologist or hydrologist, should be consulted to help site your well. You may be able to get some technical support for free from a local or state office of geology or water resources or from a nearby school of agriculture or natural resources. Where to drill for water is an important decision. In some cases, with a well-mapped aquifer and many wells nearby, it is highly probably that you will hit good water at a certain depth. In arid regions with few wells nearby, it may be less clear. In this business, however, there are no guaranties that you will find water of sufficient yield and quality — or find it at all. So take you time in choosing a well site.
Your goal is to determine what location, depth, and well diameter is most likely to provide the best flow rate and water quality for the least money. It is important to maintain adequate clearance from septic tanks, leach field, roadways, and agricultural uses such as pastures and silos. In some cases, the building code will specify a minimum depth, setback from the property line, and distance from septic systems and other sources of contamination.
Minimum clearance from a well to a single-family home is typically 5-10 ft. and 10 ft. or more to most other buildings. Recommendations from the CDC are shown in the following table:
| Source of Contamination | Minimum Distance to Well |
| Septic Tank, Leach Field | 50 ft. |
| Livestock yards, Silos | 50 ft. |
| Petroleum Tanks, Liquid-Tight Manure Storage and Fertilizer Storage and Handling | 100 ft. |
| Manure stacks | 250 ft. |
Some jurisdictions require the well to be uphill from the septic system, a commonsense idea, but not always feasible on small lots where you will inevitably be downhill from someone else’s septic system if not your own. Regardless of code requirements, you will want to follow industry standards and a professional’s recommendations for a safe and dependable water source. Read more on Well Clearances.
There are also practical concerns about distance from the house and access of drilling equipment and for maintenance. A site far from the house will increase the costs of wiring and plumbing from well to house. In addition, you may have preferences, such as not wanting the well in your front yard or in the middle of your future garden – so make sure you approve of the well site before drilling begins.
DUG WELLS
In some rural areas, homeowners still get their water from shallow, dug wells. Historically, these were dug by hand to just below the water table and lined with fieldstone, brick, or interlocking concrete tile (in newer wells), and capped with wood, stone, or concrete cover. They were typically 3 or 4 feet in diameter and typically from 10 to 30 or so feet deep, but in some cases were over 50 ft. deep. In the old days, a bucket or hand pump was commonly used, but most now use an electric pump.
Dug wells typically penetrate into just the top layer of the aquifer or into a small perched water table, which is separated from the larger aquifer below by an impermeable layer of soil. Water levels in these wells tend to fluctuate with seasonal variations in the water table and may dry up during extended dry spells. Modern shallow wells are typically excavated or bored with power equipment and lined with concrete tile. Because these can go deeper into the water table, they can produce a more reliable water supply than hand-dug wells.
Because traditional dug wells typically draw on shallow groundwater and lack a continuous casing, they are highly susceptible to contamination from nearby septic systems and from surface sources such as agricultural runoff, lawn chemicals, and other pollutants. However, dug wells can produce high-quality water they are designed and located properly.
Dug wells should have a sealed casing and cover, and be located at least 25 feet away from ponds or streams. They should be uphill from and at least 100 feet away from sources of contamination including septic systems, livestock, and fuel tanks . If located on a slope, create a berm of clay soil around the the well to divert surface runoff away from the well(see illustration).
For safety and good performance, dug wells used for drinking water should
• be dug during the dry season to reach deep enough into the water table
• have a watertight casing, such as large-diameter precast-concrete pipe, which sits on a sand or gravel base at the well bottom
• be disinfected with chlorine when new or after repairs are made
• be located on high ground, not subject to flooding, and sloped away in all directions from the well
• have a tight-fitting metal or concrete cover at the top of the casing, about one foot above the ground
• have a pump in the inside your house or in a pump house to protect equipment, storage tank, and piping
• use a pitless adapter in cold regions to provide a frost-proof, sanitary seal to the water line
• be 100 feet away from farm animals, cesspools, or leach fields
• be 75 feet away from property you do not control
• be 25 to 50 feet away from drainage ditches, culverts, streams, or ponds
DRIVEN WELLS
Where conditions are right, driven wells may offer an an economical alternative to a drilled well. Also called “sand point” wells, these are often used for cabins or vacation cottages where there is groundwater within 15 to 30 feet of the surface. They are made by driving a small-diameter pipe, by hand or power tools, into water-bearing sand or gravel that lies above the bedrock. A screened well point, designed to filter out sediment, is typically attached to the bottom of the pipe before driving.
Under favorable conditions, the pipe can be driven up to about 30 feet by hand, and 50 or more feet with a powered post driver. Typically, installers use five- or six-foot lengths of galvanized pipe with a cap on the end being hit to prevent damage to the threads. Each new section of pipe is added with a coupling to the one below. Sandy soils are the easiest to drive through. Clay will require power equipment.
There are a variety of ways to complete a driven well. Often the connection to the discharge pipe is made underground using a pitless adaptor. The access pit must be dug around the well to below the frost line in cold climates. Depending on local codes the pit can later be backfilled or can be lined with concrete tile and cap, similar to a dug well. The pump may be located inside the home or on top of the well within the concrete tile or a pump house.
Because these wells are simple and inexpensive, some people drill two and plumb them together for a better yield. However, like dug wells, they reach only shallow water, making them susceptible to contamination from surface sources.
DRILLED WELLS
Over 15 million homes in the US draw their water from private wells and millions more use water drawn from municipal wells. Nearly all of these are drilled wells (see illustration). Most modern wells are drilled by rotary drill machines, which can easily drill through solid rock.
In some cases, a cable-tool drilling rig is used, also referred to as a percussion or “pounder” machine. In this technique, a heavy bit attached to the bottom of a wire cable is repeatedly raised and dropped, pounding its way down through the earth. Most private wells range from 100 to 500 feet deep, but in rare cases can exceed 1,000 feet.
The well design will depend on the specific geological conditions at the site. Most wells are drilled an inch or two wider than the casing diameter, which is commonly 6 inches. In the upper portion of the well, unless it is solid rock, the space between the casing and the drilled hole is later “grouted” with cement or bentonite (a special expansive clay). This seals the drilling hole to prevent contaminated surface water from migrating down the well casing to the aquifer. Depending on conditions, the bottom of the well may be drilled into solid rock, drawing its water from cracks in the rock.
Missy says
Minimum Well Yield To Get Mortgage?
I am considering buying a property with a drilled well at about 750 feet. The papers indicate a 2gpm, is this a problem? I saw elsewhere that I might have trouble getting a mortgage with a 2gpm well. Thanks for your help!
buildingadvisor says
I believe that loans from the Federal Housing Administration (FHA) require a flow rate of 3-5 gallons per minute (gpm) for existing wells and 5 gpm for new wells. A sustained yield of at least 5 gpm for two hours is considered suitable for residential usage.
Typical kitchen faucets and showers use 2-3 gpm, so your well would have trouble meeting normal loads.
Private lenders may have different rules about well yield, which you can find out by speaking with the loan officer at your bank. Also check with your municipality’s building department about state and local standards for well yield.
Sometimes adding a storage tank provides enough water to meet household demand. Like a water heater, once the tank is depleted you would need to wait for it be replenished.
In some cases, well yield can be improved by repairs or upgrades to the existing well — or drilling a deeper or wider well. Adding a second well is also an option. Two one-gallon wells can be combined for a 2 GPM flow rate.
In a bedrock well, hydrofracking — pumping pressurized water into the well — can often improve the yield. High-pressure water can also be used to reduce mineral buildup that is blocking pipes.
t’s also possible that the pump needs to be placed deeper in the well – if the water level has fallen — or a larger pump is needed if the house is far from the well or the underground piping too small.
If the well performed well in the past, the problem may be blockages from one of the following:
• Buildup of scale in the pipes from minerals in the water
• Plugging of the screens or intake by sand or silt
• Fouling of the screens or intake by bacteria
The treatment will depend on the nature of the blockage. High-pressure water or mechanical scrubbers may be used for physical blockages. If bacteria is present, the well will need to be disinfected and flushed.
Have a well driller or specialist inspect the well to determine the best course of action.
Dilson B Oliveira says
Is Deeper Artesian Well Better?
Besides cost, what’s the advantage of drilling deeper if artesian water was found at 328 feet?
Does deeper water, from artesian wells, have higher flow rates and pressure?
Are flowing wells that are drilled deep in the ground less prone to developing flow problems? Are they easier to deal with. In what aspect?
Drilling in bedrock locations, the rock allows for the easy installation of the seal? Meaning?
Thank you!
buildingadvisor says
In general, if you have good water quality and adequate flow rates for your needs then there is no need to drill deeper. However, well design is very site specific and there may be valid reasons that your well driller is advising that you go deeper. For example, some artesian wells only flow intermittently and a deeper aquifer may have better pressure.
The obvious advantage of a flowing artesian well is that you do not need a well pump to bring water to the surface as long as adequate pressures are maintained over time. If the well is properly designed and managed, the water source may last indefinitely.
It is important that the well casing be well-sealed to the confining layer to prevent pressurized well water from leaking outside the casing, potentially depleting the aquifer. Well driller have techniques to seal to range of materials they encounter. Bedrock has the advantage of being very stable and easy to permanently seal to with cement-grout.
Andy Mege says
New Well Has Cloudy Water & Odors
We just got a new well installed, 120 feet deep and in a gravel bed. We have been using the well for a week, water is still a little cloudy and smells kinda like steel… the smell if your grinding steel.. Any comments
buildingadvisor says
First you need to determine whether the cloudiness is caused by air bubbles, which are harmless, or particulate matter such as sand and silt — also called “turbidity.” Let a jar of water sit overnight — up to 24 hours — and the particles will settle to the bottom. You will also see particles settle to the bottom of the your toilet bowl after several hours.
While turbid, cloudy water is unappealing to drink, it usually does not present a health hazard from a deep well unless it is contaminated by ground water. Just to be safe a water test is always a good idea. In most cases, your local health department will provide these for a nominal fee. In rare cases, mainly in areas with oil or gas wells, turbidity is caused by methane gas, which must be removed for safety.
Turbidity can have many possible causes — ranging from dissolved material in the aquifer to a cracked or unsealed well casing. In wells that terminate in loose material, a gravel pack and well screen filter out most of the particles providing clear water. These are not needed in wells that terminate in solid or fractured rock.
During the process of well development, the well driller treats the well to improve flow and clear the water of turbidity. A number of methods are used depending on the specific conditions at the bottom of the well. With very fine silt, however, some wells are difficult to clear of turbidity. If the well driller did not properly develop the well, then it is his responsibility to complete the job.
In some cases, the problem is fixed by running the well at full capacity (overpumping) for 24 hours or longer – often with a spigot installed at the well head. In difficult cases, they may lower a camera down the well to get a detailed look at the source of the problem, such as a damaged well screen. Sometimes using a lower GPM pump or limiting the flow rate with a ball valve is effective.
If all else fails, filtration or reverse osmosis can be used to clear the water. However, whole-house systems can be expensive to install and operate.
As for the metallic taste, hopefully that will clear up with additional well development. In some cases the metallic taste is due to minerals in the water or copper leached from the plumbing system by highly acidic water. Your water test should help you determine the source of the metallic taste and the best approach to treating the problem.
Andy Mege says
Thank you for the response and guidance…. Ran the water for about 36 hours, nice clear water. kept filling jars every day, back to cloudy again and metal taste is back… Are well drillers supposed to us bentonite at the well casing? Back in the 80’s, I installed the Turbidity meters on the Reading, Pa. water treatment plant…. Got to do and learn so much cool stuff back then…
buildingadvisor says
Yes, grouting is standard practice now in residential water wells and required by law in many states – check with your local health department or whoever issues well permits in your area.
The two main types of grout are bentonite and neat cement. Neat cement is generally used in dry conditions where there is not enough subsurface moisture to hydrate the bentonite. Depending on conditions, bentonite can either be placed dry or mixed with water and cement in a slurry. The goal is to seal the annular hole above the aquifer. The seal may run all the way to the ground surface or part way depending on soil conditions and local regulations.
It is definitely the well driller’s job to seal and “develop” the well so it provides clear water, free of sediment or surface contaminants. There are a number of approaches to well development depending on the borehole and aquifer characteristics. In some cases, the best solution is to reduce the well pump flow rate and store the water in a large non-pressurized holding tank. A second pump is needed to supply the house.
Is it possible that the metallic taste is iron or manganese in the water? If so, filtration may be your best option.
You can find in-depth discussions on well development at this link.
RL says
How to Size Well Pump & Complete a Well?
I have a property in the Philippines. On my land I have a well approximately 30 feet deep I want to make it deeper by another 30 feet
(20 meters)
I intend to drop into the well a 6 inch diameter PVC pipe, then find a pump to bring the water up to the surface into a tank..
What size pump would I require ..and what would I need to fill in the sides of the pipe.
The water is clear…but I assume there will be amount of sediment at the bottom. The well itself is around 2 feet in diameter.
Thank you.
RL, United kingdom
buildingadvisor says
A 5- or 6-inch casing typically takes a 4-inch submersible pump, with a pump rate (gpm) that ideally equals the maximum usage of the home – assuming the well yield can meet the pump’s capacity. So the well’s recovery rate should be determined before sizing the pump. In the US, the average family of 3-4 people require 5-8 gpm. Over-pumping can increase sediment clogging and corrosion, as well as draw down the aquifer.
The annular space around the pipe is typically sealed with bentonite grout or sand-cement grout to keep surface water from contaminating the well. In addition to protecting the well water, the grout helps protect the relatively weak PVC well casing from damage.
Where the bottom of the well is located in loose material, rather than solid rock, it’s best to install a well screen. The screen allows clean water to enter the well, while filtering out sand and silt. This provides cleaner water to the home and prevents excess wear of the well pump and home appliances.
Read more on Completing the Well System
LJ says
Cement Plug In Drilled Well a Mystery
We bought a property that has a drilled well. There are coliforms in the water and we wanted to do a flush of the system, but when we took the cap off the pipe, where the pump cables go in, there is a type of rocky cement cap/blockage 5 feet down. There is no way to do a flush unless it’s removed….I think. Water pump guys won’t touch it, a local well water company says they have never seen it before and we are stuck with trying to get responses from other companies. ANY info, advise would be greatly appreciated!
buildingadvisor says
Sounds like someone plugged the well for some reason, but it may be difficult to determine why. Abandoned wells are often plugged to prevent contamination of the groundwater. Flowing artesian wells, if abandoned, are often plugged and capped to prevent problems with erosion or depletion of the aquifer.
Wells are typically plugged with bentonite clay, cement, or concrete grout. With deeper drilled wells, the deeper sections may first be filled with with less expensive fill materials and the cement or clay sealer used only in the upper section.
It does not sound like you are dealing with an abandoned well, however, so the presence of the cement material is a mystery. Any suggestions from readers would be appreciated!
If you can check with the previous owner, that might be helpful. Also, you may be able to find the name of the originally driller from the town, assuming they issued a permit for the well. They may be able to provide some insight.
Cody says
Concerns About Flowing Artesian Well
I’m getting a house built and the contractor already had a well in place. He said it’s an artisan well and runs at 100gpm. He showed me the well driller paper work that says that. It’s drilled a little over 100ft. I’ve never heard of anyone in my area with a well that doesn’t need or have a pump. Is there a way to confirm we will not need a pump? Do artisan wells run dry faster? I’m just really worried about having a well without a pump. Any insight or guidance would be greatly appreciated.
buildingadvisor says
A flowing artesian well is one where the pressure in a confined aquifer is great enough to force water to the surface without a well pump.
In general, that’s a good thing as you will not need a well pump, but the final cost of the complete well system can end up being higher than a conventional pumped well. That’s because of the need to properly seal the well casing and control the flow. With a flowing well, the casing must extend all the way from the surface to the confined aquifer and properly sealed to prevent any leakage. The sealing requirements will depend on the local topography. Also, the wellhead assembly may be more complicated than in a conventional drilled well and freeze protection will be needed in cold climates.
Uncontrolled flow or leakage below or above ground can cause a number of problems such as erosion and land subsidence (sinking). It can also cause the well to lose pressure over time.
The higher the water pressure, the greater the challenge to properly seal the well and control the flow. It sounds like you have a high-pressure well, so I would want to get additional information from the well driller about costs and potential problems.
If you still have questions, you might want to get the opinion of a licensed hydrogeologist. You may be able to get some free advice from your state’s water well program or from one of the national water well programs such as Wellcare or Wellowner.org.
You can find a good primer on flowing artesian wells at this link.
buildingadvisor says
Minimum Distance from Well To Pond
If there was a storm water detention pond built 50 ft. away from my well head, would that be okay?
buildingadvisor says
The minimum recommended setback from a drilled water well to a leach field or other potential sources of contamination is typically 50 to100 ft., depending on the local regulations and the type of pollutant. For particularly noxious materials such as stored fuels, pesticides, or silage, 100 to 250 ft. may be required.
Unless you have particularly polluted runoff in your area, the water temporarily help in a detention pond should be no worse than other surface water that your well is exposed to. Assuming the well is properly cased and protected, 50 ft. of clearance should be adequate. Testing your well water every year or two is always a good idea to make sure it meets quality standards and does not require treatment. Most local health departments provide this service for a nominal fee.
Read more on Well Clearances.
Guy Beattie says
Should I Fill Old Well In Basement?
Good Morning , I have a well inside my basement. It is about 2-1/2 ft. wide and about 6 or 7 ft. deep. It has a round concrete casing. It fills very high when we receive a heavy rain had has never been dry. I even tried draining it out once for a full day with no luck. We do not use it as the previous owner drilled a well outside the house before we bought it.
I am unclear if I should seal it up or not. My basement is a floating slab and concrete block. I do have a separate stump pump set up for underground water build-up. I do have a pump in the well also set to come on and pump water out of the house when it reaches a certain level.
Your Thoughts?
buildingadvisor says
From your description, this sounds like shallow dug well. The changes in water level after a heavy rain may indicate a change in the water table, a change in the local water level around the foundation, or a combination of the two.
It sounds like you have a separate sump pit with a pump to handle excess water levels in the basement.
There’s no particular need to fill the old well, except perhaps to reduce a safety hazard. You can cap the bottom with concrete or bentonite if you want to try to keep the old well from filling. Then fill the rest with sand or other clean fill.
You can leave a space at the top with a pump to act as a second sump pit if you feel you have the need.
If water levels are rising regular to above the level of basement floor, you should take a close look at your site drainage and foundation drainage. Either you have a very high water table under the house or you are not directing yard and roof water away from the house from rainstorms and snow melt.
Sometimes a simple fix like adding extensions to the bottom of your downspouts can be effective at getting water away from the foundation. Other times, more extensive grading and drainage work is required.
Matthew Guina says
What Should It Cost to Drill A Well?
I am looking at getting a well drilled on our new property. We have only talked to one driller at the moment, but his lowest quote came back at $15,000 for a 220 foot deep well with 6″ casing. Other numbers he gave me were heading towards the $40,000 range. That doesn’t include any pump or filtration systems. The property has about 10 out of the 40 acres designated as wetlands, so doesn’t that mean the water should be pretty close to the surface? I can’t imagine having to drill over 500 feet in Washington. I appreciate your help!
buildingadvisor says
Having wetlands on your land often indicates that the top of the water table is near the ground surface, but not always. Wetlands tend to act like a sponge, storing and purifying water before it seeps back into the aquifer.
Wetlands and groundwater can interact in a variety of ways. With a water table near the ground surface, water may be flowing from the wetlands down into the aquifer or from the aquifer to the wetlands – or either way depending on fluctuations in the water table.
In other cases, however, the wetlands receive all or most of their water from surface water and are disconnected from the groundwater. In this case, the groundwater could be far below the surface.
So the presence of wetlands does not reliably predict the well depth required to supply the water quality and yield required. Local well drillers are generally a good source of this knowledge, but you may want to get the opinion of an independent third party. Your state or county health/environmental department may have a hydrologist on staff or be able to provide groundwater resource maps or other useful information about your area.
In general, deep wells provide more water and better water quality than shallow wells. Deep wells (based on the depth of the casing) are better protected from ground contamination. But I would question why your driller thinks a 250 ft. well is necessary.
Also, on a 40 acre site, you have better control of surface water conditions than in a densely settled area. So a shallower well may provide perfectly good water – especially if the land uphill (upgradient) from your well is undeveloped. Water in the aquifer flows very slowly and you many need a hydrologist to determine its direction of flow.
On the $15,000 estimate, will you pay less if the driller finds good water at less than 250 feet? You are already at the high end of drilling costs per foot. Also, I’m not sure what the $40,000 estimate includes, but it’s best to get the full price to complete the well system. Again, your bid is on the high side and you’re not even getting a pump. What else is missing from the bid? Unless you have particularly challenging drilling conditions or other costly issues, I would shop around for other bids.
C wisema says
How to Test Well & Septic on New Lot
I am looking at a piece of land that says it has a well and septic already on it.
What questions do I need to ask to make sure they are within code and don”t need to be replaced or repaired?
buildingadvisor says
You should certainly ask about the well and septic system and ask for any test results that the seller can provide. However, you should also make well and septic inspection a contingency of your offer, giving you the right to make more detailed inspections if you feel that is necessary.
If there is no house on the land, there’s a good chance that the well was drilled, but the well system was not completed. In that case, the well yield has probably been measured and logged, but the well will still need a pump, plumbing lines to the house, a pressure tank, and maybe a water softener or other type of filter. The cost of this work can exceed the cost of drilling the hole in the ground, so it’s something to budget for in your building project. In this case you will want documentation of the well yield and water quality.
With a completed well system connected to a house, your main concerns are well yield (measured in gallons per minute), water quality, and the condition of the equipment, including the well pump, plumbing, pressure tank, and any filtration equipment. The original well yield might be contained in a log that was recorded when the well was drilled, but it may no longer be accurate if it is decades old. A certified well contractor can inspect the well equipment and perform the necessary tests. Water quality testing is normally performed by bringing a water sample to the local health department – contact them for specifics.
Septic systems are more difficult to evaluate. While it is easy to determine if a system has failed, it’s difficult to say how much longer a system will last. The best indicators are the age of a system, the type of tank (concrete is best), and how well the system was maintained.
Ask how often the system was inspected and pumped and whether they have any records of this. The average life of a drain field is 20 to 30 years, but there are many variables. Again, a professional inspection is a good idea but will tell you more about the system’s current condition than its lifespan.
Read more on Testing Wells and Septic Systems and Lifespan of a Septic System
A state-by-state list of licensed well contractors in the US. and Canada, and well regulations, is published by the Water Systems Council.
Jeff says
Why Has Sand Point Well Run Dry?
I live close to a river and everyone uses a sand point. Seems everyone has 1-1/4″ galvanized pipe that is goes 50 feet deep (not 25′ or less) and use a 1/2 hp shallow pump with a pressurized tank. How do these work being they are 50′ (some deeper) and shallow pumps say they only work 25′ or less? Anyway, I woke up and had no water so I went down into my pit as I call it (my pit is deeper than everyone else’s guessing around 12′ to floor of pit where pump and tank are located) and pump was running and pipes were super hot. Check valve is at the floor of the pit where pipe come out of ground then small pipe from valve to pump. I made sure check valve was ok (is fairly new) then but it back on pipe and tried using a brand new pitcher pump and still no water. Oh forgot to say my pipe is 1 1/2″ and not 1 1/4″ like most. None of my neighbors are having any problems with their water so I assume mine is not dried up. The pipes in ground are very old but everything from check valve up was replaced new about 7-8 months ago. I also tried to run water into pipe with neighbors hose when I had the check valve off letting it run for 15 minutes and it just kept running not filling the pipe. Is it clogged or did it dry up. I have no clue how to figure out which. So confused and don’t know what to do next.
buildingadvisor says
Sorry to hear about your well problems. Sand point (driven) wells are uncommon in my area and are mostly used nowadays for non-potable water such as lawn or garden watering. One reason is that driven point wells are most commonly used where the water table is fairly shallow and are, therefore, vulnerable to contamination from surface pollutants. If you are using this for potable water, make sure you disinfect and test the well water after doing any work on the well.
It’s difficult to diagnose this type of problem from a distance, but I can suggest a few things to check.
There are number of possible causes: a clogged well point, an air leak or break in the line causing a pumping failure, or a drop in the water table. Since your well has worked fine in the past, and your neighbors’ well are still producing, it is unlikely that the water source has dried up – although it is possible that the water table has dropped below your well point – especially if your area is experiencing drought conditions. In some areas, the water table can vary from 5-10 ft. in a normal year.
First, it sounds like your pump is running dry and heating up the pipes. Running a pump dry can destroy it pretty quickly. So the first thing I would try is to prime the pump. You can read more on priming a pump at our sister site, Inspectapedia.
Next, see whether you can restore the well by unclogging the well point, which usually has a screen or strainer to keep sand out of the well. The bottom of the well and screen may be clogged with silt, which is a dense material made from very fine particles of sand. Unplugging a well point is generally done by forcing pressurized water or air down the well, as described at this link.
It is also possible that the well point or screen is clogged with calcium or rust. These require commercial chemicals to remove and the work is best done by a well drilling professional.
The fact that you can run water down the pipe for 15 minutes without filling the pipe may mean that you have a break in the old pipe in the ground. In that case, you just sending water into the surrounding sand and gravel soil. The break would also create a vacuum leak disabling your pump from working. If that’s the case, you will need to drive a new well point nearby and connect it to your existing check valve and pump. With a new well point, you should be good to go, assuming you reach to a few feet below the seasonal low water table.
If you don’t want to hire a well driller to take a look, you might try your county’s Dept. of Environmental Quality or Health, which may provide some technical advice to homeowners with water well problems.
You can find a good overview of sand point (driven) wells at this link.
Layny says
Cost of Drilled Well
I live in SW Florida (Lee Co.) I’m planning to build a small home. I am pricing having a well drilled. It will be a new individual well. I don’t know how to tell if I’m getting a fair price or not. Please help.
buildingadvisor says
The average cost of a complete well system ranges from $5,000 to $10,000 nationally, but can be double that in difficult or high-cost areas. However many factors can drive the price up including difficult drilling conditions, well depth, and extra hardware to boost the supply and pressure if the well yield is too low. Whole-house water treatment, if needed, will add another $1,500 to $3,000 to the total.
Drilling costs are typically by the foot, so the depth of surrounding wells is a good guide to the basic drilling cost, as well as water quality and yield. When getting prices, however, make sure you price out the entire well system, which is a much higher than the cost of drilling a hole with casing and cap. By the time you add the pump, wiring, trenching and piping to house, pressure tank, and controls, the cost of cost of “drilling a well” is often doubled.
The well driller’s quote will typically NOT include the entire system — just the hole in the ground, the well casing, and cap, so you may need to get separate quotes from a plumber and electrician to complete the well system.
Heidi says
How Deep to Drill Well?
We are currently in the process of looking for someone to hire to have our well drilled. We have a dug well currently that is only 12ft into the ground and we have had a serious period of drought where we live so our well has dried up. We are between 2 contractors right now, one is more of the old school type and the other is a well established multi person company. The older contractor has us only drilling down 200ft for water where the newer contractor said that 500ft would be their minimum to find water. Obviously finding water at either depth is not guaranteed, but most wells in our area are 500ft. The older contractor told us that is because of the newer machinery and how it works as opposed to the older machinery. Who to go with and what would be your best recommendation? Thank you.
buildingadvisor says
The short answer is I don’t know. There are many variables that determine the depth, yield, and quality of water in a drilled well and these vary regionally and locally. Local well drillers are often the best source of information on this topic, so it’s a challenge when you get two different stories.
In some states, you may be able to get help from a hydrologist at the Dept. of Environmental Quality (DEQ) or Dept. of Natural Resources. Other resources are the local USGS office or the geology department at a local university.
My gut feeling is to trust the larger company with the more conservative estimate. If most wells in your area are 500 feet, expecting good water at 200 feet sounds unrealistic. The depth of surrounding wells is the best indicator of where to find water. Also, a deeper well generally has a higher yield and better resistance to droughts. Shallower wells are also more vulnerable to contamination.
An experienced driller can get a good indication of when they have reached the aquifer and can stop drilling. I’d suggest asking both drillers about what yield they expect, what diameter they are drilling, and what testing they will provide for yield and quality, and what exactly their bids include. The well, itself, is just a hole in the ground. The completed well system includes casing, screen, well development, pump, trenching, plumbing, and pressure tank to make use of the water in your home.
Also, ask what type of warranty they offer on the pump and pressure tank, as well as the well casing and equipment. And don’t forget to check references!
You can read more about well depth at this link.
Jasper Whiteside says
How To Protect Dug Well From Contaminants?
It makes sense that a dug well would be susceptible to nearby pollutants. I wonder if there have been any advances that make it more affordable to protect the water supply. I suppose that that would ruin the effectiveness of the well, wouldn’t it?
buildingadvisor says
Modern dug wells with sealed casings and proper placement away from sources of pollution are much safer than the traditional shallow well lined with stones or bricks and accessed with a bucket. Modern wells also go further below the water table and tend to have better water yield and quality.
I’m not aware of any advances for shallow dug wells other than the ones mentioned here: sealed concrete casing, tight-fitting cover, disinfecting when new, and locating the well a safe distance, and uphill from, sources of pollution such as septic systems and farm animals. If the well is on sloping land, you should also make a soil berm around the well to divert surface water away from the well casing. When the well is new, or after repairs, it should be disinfected with household bleach and tested for bacterial and other types of contamination. You can read about the disinfecting procedure here along with other good tips on dug wells.
In Vermont where I live dug wells are still commonly used in some rural areas. They can produce good water, but should be regularly tested for water quality. All well water should be tested every year or two for watery purity. With a dug well, I would recommend testing once a year, at least for the first few years. Most town health departments provide low-cost water tests for residents with well water.
One thing to consider is that the cost of a drilled well, if you don’t need to drill too deep, may not be that much more than a well-deigned, sanitary dug well, so you might want to consider a drilled well, which is a more reliable source of pure water.
Best of luck with your water well!
silvia scherer says
Drilling Well in Clay Soil
They are drilling my well right now and have drilled 300 feet. I saw a lot of wet, gray material which the workers said was clay from deep down. They said they encountered it around 300 ft. and when they got to 380 ft. they called their boss. He said to go 20 more feet and to stop there and install the casing. So, my question is, what does clay mean for my well? Is it a problem?
buildingadvisor says
Drilled wells draw their water from underground water formations called “aquifers”. In general, the best water yields come from porous materials that allow the water to flow freely to replenish to well. These include course sand, gravel, and sandstone, as well as fractured stone.
Soils like clay and silt with small, tightly packed particles do not generally provide good well yield. To compensate for a low water yield, you can increase the amount of water storage by using a deeper well and larger diameter well bore or adding an intermediate storage tank (in addition to the pressure tank).
Also you need to pay special attention to the well screen. the filter at the well head, making sure it is designed to filter out the clay particles.
Before they complete the well, you should contact the boss, yourself, as he is the one making the decisions. Aak whether this well will provide adequate yield for your needs and what type of screen will be best for providing clean water. Also find out why he stopped drilling at 400 feet and whether wells of this depth are typical in your area. This is pretty deep (and expensive) well, so it would be a shame if you cannot get an adequate supply of good quality water.
You can read more at the following links: Aquifers-USGS Water Systems Council Low-Yielding Wells
Ezekiel E.A. says
Inadequate Flow at 300 Feet
I unsuccessfully drilled for water on my property. I drilled over 300ft, but a neighbor whose property is located about 350 ft. away from mine succeeded to get good water. A key problem, in my view, is that local drillers in my area are not that knowledgable, but rather “learn by doing”. My question: Is there a way to really find out whether there is water on a particular piece of land? Many thanks
buildingadvisor says
Knowing where to drill for water is a matter of both art and science. An experienced well driller is usually a good resource, but maybe not so in your case. However, even the most experienced well driller can strike out from time to time, as water flow underground is never 100% predictable. No one can guarantee that a drilled well will produce water – or the depth you will need to drill to find a suitable yield. However, with a good well so nearby, it is highly unlikely that your property is without water.
An understanding of the hydrogeology of the area is a good starting point. Excess rainwater that percolates though the soil collects in porous soils or in cracks in the rocks. These collection zones are called aquifers, which can extend for great distances. Many factors affect the size and shape of aquifers and how quickly they refill when water is pumped out. The amount of rainfall, the types of soil and rock, and surface topography are the main factors that determine the depth and characteristics of the local aquifer. The upper surface of the aquifer, or “water table” usually more-or-less follows the contour of the land surface but not always.
Some general principles for finding a good water source at a reasonable depth are:
• The more rain an area has, the more likely you are to find a healthy aquifer.
• Nearby wells are a good indication of the depth and yield of a well on your property. A well drilled between two nearby wells will probably hit the same aquifer. With data on multiple wells in the area, you can draw a rough map of the local aquifer. Aquifers range from hundreds of meters to hundreds of kilometers in length and width.
• Lower areas are generally better than hilltops for drilling. Well drillers often look for the low points, valleys, or “draws” on the land where water naturally collects to recharge the aquifer.
• Underground layers of porous sand and gravel, and soft rock such as limestone or sandstone, are better than hard rock such as granite.
• Nearby surface water in rivers, lakes, ponds, or wetlands, as well as wet areas such as springs and seeps can help indicate the elevation of nearby groundwater.
• In arid areas, large trees such as willows and cottonwoods can indicate the presence of underground water. Other water-loving plants can provide clues.
Experienced well drillers are usually a good source of this information from a practical perspective. They know local drilling conditions and well yields. Most keep logs of the depth and yield of wells they have drilled, giving them a good sense of what to expect. A more scientific approach is taken by hydrogeologists, who study and map the flow and quality of underground water along with the geology. Some local governments, typically the department of health, environmental quality, or geological services, can provide water availability maps or other data to help in locating water. A state or county hydrologist or hydrogeologist may be available to assist as well.
You can also hire a hydrogeologist for a consult. In some cases, they will use aerial photography or high-tech methods to gauge underground conditions. However, neither well drillers or geologists can say with 100% accuracy what you will find when drilling. In the US, some well drillers will guarantee success for a fixed price, but that may not be an option where you are located.
Once you find someone you trust – whether another driller or a hydrogeologist – they can advise you on whether you will be better off drilling deeper or trying a new location. Best of luck with your drilling efforts!
Melanie says
Chance of Success After Dry Holes?
We are considering purchasing a home in poor condition on a beautiful rural lot, next to a stream. We would want to renovate the existing property or tear it down and build a new home. The county health official told us, “… a replacement well was apparently attempted to be drilled in 2002. They were dry holes, so I believe there still is only the OLD well on this property, which may be unacceptable.”
From the information on this site, I believe this is a traditional well and that it would not be acceptable. Do “dry holes” mean that a well cannot be dug or could it mean that the driller was incompetent?
buildingadvisor says
Based on your inquiry, it sounds like the original well was an older “dug well”, which may not meet current standards for domestic wells in your area. Your county health official should be able to tell you what you would need to do to bring the well into compliance, as an alternative to a deep drilled well.
Dug wells are typically no more than 10 to 30 feet deep and often lined with stone or brick. Because their lining is rarely watertight, and the space around the well (between the casing and surrounding soil) is not sealed, most dug wells are highly vulnerable to contamination from surface water. And since they only reach just a little below the water table, they can run dry during dry weather. Today, dug wells are used more for livestock or irrigation than for domestic water supply.
Older dug wells can be made more sanitary by installing a water-tight casing with a concrete cap, and sealing the area outside the well casing with cement grout or bentonite clay. The casing should extend at least a foot above grade and the land immediately around the well should be sloped to prevent water from collecting by the well pit. The pump is best located in the home or in a pump house away from the well. However, the money required to rehabilitate a dug well is usually better spent on a new deep well.
Well drilling is both art and science, and success is never guaranteed 100%. The fact that the last driller came up with dry holes does not mean that the driller was incompetent or that another hole will be successful. Perhaps he needed to drill deeper or try another location on the site. An experienced local well driller should have a good idea of the local geology and aquifer characteristics. In areas of the country with normal rainfall, drillers rarely have to go more than 200 feet deep
I would suggest that you talk to a couple of local well drillers (including the one that came up dry) to get their perspective. Neighbors may also be able to provide you with useful information about well depth, flow rates, and water quality on their land – a good indicator of what to expect on your land.
You may also be able to find a well driller who will guarantee a well with a minimum, acceptable flow rate for a fixed price. Also, you could make your offer contingent on drilling a successful well. You would put some money at risk, but less than if you buy a lot without potable water. Also, the initial drilling costs a lot less than a completed well system, so the cost to look for water may be less than you think.