Well Water Information

Mar 27th 2017

Approximately 15% of Americans obtain their drinking water from a private well. These wells are not subject to the EPA Safe Drinking Water Act (SDWA) and the Primary and Secondary Drinking Water Regulations. No regulatory officials are checking and monitoring private wells for water quality and safety. Some states and local governments may have established regulations to protect well owners. Check with your State and local Department of Environmental Services or Board of Health resources for further information. Basically, if your drinking water supply is from a private well, it is your responsibility to maintain and monitor the well to ensure safe, high quality drinking water.

Proper well construction and continued maintenance are keys to the safety of your water supply. The well should be located so rainwater flows away from it. Rainwater can pick up harmful bacteria and chemicals on the land’s surface. If this water pools near your well, it can seep into it, potentially causing contamination of undesirable substances. It’s better to maintain your well, find problems early, and correct them to protect your well’s performance. Keep up-to-date records of well installation and repairs plus pumping and water tests.

Protect your own well area. Be careful about storage and disposal of household and lawn care chemicals and wastes. Good farmers and gardeners minimize the use of fertilizers and pesticides. Take steps to reduce erosion and prevent surface water runoff. Regularly check underground storage tanks that hold home heating oil, diesel, or gasoline. Make sure your well is protected from the wastes of livestock, pets, and wildlife. To keep your well safe, you must be sure possible sources of contamination are not close by. Experts suggest the following distances as a minimum for protection:

  • Septic Tanks - 50 feet
  • Livestock Yards, Silos, Septic Leach Fields - 50 feet
  • Petroleum Tanks, Liquid-Tight Manure Storage and Fertilizer Storage and Handling - 100 feet
  • Manure Stacks - 250 feet

Types of Wells

Dug Wells - Dug wells are holes in the ground dug by shovel or backhoe. Historically, a dug well was excavated below the groundwater table until incoming water exceeded the digger’s bailing rate. The well was then lined (cased) with stones, brick, tile, or other material to prevent collapse. It was covered with a cap of wood, stone, or concrete. Since it is so difficult to dig beneath the ground water table, dug wells are not very deep. Typically, they are only 10 to 30 feet deep. Being so shallow, dug wells have the highest risk of becoming contaminated. To minimize the likelihood of contamination, your dug well should have certain features. These features help to prevent contaminants from traveling along the outside of the casing or through the casing and into the well.

Driven Wells - Lengths of 2"-3" diameter metal pipes are driven into the ground with a screened endpoint to allow water to enter the piping. Driven wells pull water from the water-saturated zone above the bedrock. Driven wells can be deeper than dug wells. They are typically 30 to 50 feet deep and are usually located in areas with thick sand and gravel deposits where the ground water table is within 15 feet of the ground’s surface. Although deeper than dug wells, driven wells are still relatively shallow and have a moderate-to-high risk of contamination from nearby land activities.

Drilled Wells - Drilled wells penetrate about 100-400 feet into the bedrock. To serve as a water supply, a drilled well must intersect bedrock fractures containing ground water. In low yield situations, Hydrofracting may be used. This process applies water or air under pressure into your well to open up existing fractures near your well and can even create new ones. The well casing is usually metal or plastic pipe, six inches in diameter that extends into the bedrock to prevent shallow ground water from entering the well. By law, the casing has to extend at least 18 feet into the ground, with at least five feet extending into the bedrock. The casing should also extend a foot or two above the ground’s surface. A sealant, such as cement grout or bentonite clay, should be poured along the outside of the casing to the top of the well. The well is capped to prevent surface water from entering the well. Submersible pumps, located near the bottom of the well inside the casing, are most commonly used in drilled wells.

Well Water Contamination

Water fills the spaces between rocks and soils and creates an Aquifer. This water primarily comes from rain and melting snow that soaks into the ground. The rain and melting snow flows through a "Watershed", which is the land area above the Aquifer. The source of water for wells is in the "Water Table", a line below which the ground is saturated or filled with water available for pumping.

Sources of well water contamination can be from natural and man made sources. Water moving through the underground rocks and soils can pick up undesirable levels of hardness minerals, Fluorides, Arsenic, Selenium, Iron and dissolved gasses such as Radon. Man made sources of pollution can be caused by the use of organic chemicals, chemical spills and leaking underground storage tanks.

Examples of Natural Sources of Pollution

Microorganisms - Bacteria, viruses, parasites and other microorganisms are sometimes found in water. Shallow wells, those with water close to ground level, are at most risk. Runoff, or water flowing over the land surface, may pick up these pollutants from wildlife and soils. This is often the case after flooding. Some of these organisms can cause a variety of illnesses. Symptoms include nausea and diarrhea. These can occur shortly after drinking contaminated water. The effects could be short-term yet severe (similar to food poisoning) or might recur frequently or develop slowly over a long time.

Radionuclides - radioactive elements such as uranium and radium. They may be present in underlying rock and ground water.

Radon - a gas that is a natural product of the breakdown of uranium in the soil. Radon is most dangerous when inhaled and contributes to lung cancer. Although soil is the primary source, using household water containing Radon contributes to elevated indoor Radon levels. Radon is less dangerous when consumed in water, but remains a risk to health.

Nitrates and Nitrites - high nitrate levels are usually due to human activities, but they also may be found naturally in ground water. They come from the breakdown of nitrogen compounds in the soil. Flowing ground water picks them up from the soil. Drinking large amounts of nitrates and nitrites is particularly threatening to infants (for example, when mixed in formula).

Heavy Metals - underground rocks and soils may contain arsenic, cadmium, chromium, lead, and selenium. However, these contaminants are not often found in household wells at dangerous levels from natural sources.

Fluoride - excessive consumption of naturally occurring fluoride can damage bone tissue. High levels of fluoride occur naturally in some areas. It may discolor teeth, but this is not a health risk.

Examples of Man Made Sources of Pollution

Bacteria and Nitrates - these pollutants are found in human and animal wastes. Septic tanks can cause bacterial and nitrate pollution, so can large numbers of farm animals. Both septic systems and animal manures must be carefully managed to prevent pollution. Sanitary landfills and garbage dumps are also sources. Children and some adults are at extra risk when exposed to water-born bacteria. These include the elderly and people whose immune systems are weak due to AIDS or treatments for cancer. Fertilizers can add to nitrate problems. Nitrates cause a health threat in very young infants called “blue baby” syndrome. This condition disrupts oxygen flow in the blood.

Concentrated Animal Feeding Operations (CAFOs) - the number of CAFOs, often called “factory farms,” is growing. On these farms thousands of animals are raised in a small space. The large amounts of animal wastes/manures from these farms can threaten water supplies. Strict and careful manure management is needed to prevent pathogen and nutrient problems. Salts from high levels of manures can also pollute ground water.

Heavy Metals - activities such as mining and construction can release large amounts of heavy metals into nearby ground water sources. Some older fruit orchards may contain high levels of arsenic, once used as a pesticide. At high levels, these metals pose a health risk.

Fertilizers and Pesticides - farmers use fertilizers and pesticides to promote growth and reduce insect damage. These products are also used on golf courses and suburban lawns and gardens. The chemicals in these products may end up in ground water. Such pollution depends on the types and amounts of chemicals used and how they are applied. Local environmental conditions (soil types, seasonal snow and rainfall) also affect this pollution. Many fertilizers contain forms of nitrogen that can break down into harmful nitrates. This could add to other sources of nitrates mentioned above. Some underground agricultural drainage systems collect fertilizers and pesticides. This polluted water can pose problems to ground water and local streams and rivers. In addition, chemicals used to treat buildings and homes for termites or other pests may also pose a threat. Again, the possibility of problems depends on the amount and kind of chemicals. The types of soil and the amount of water moving through the soil also play a role.

Industrial Products and Wastes: Many harmful chemicals are used widely in local business and industry. These can become drinking water pollutants if not well managed. The most common sources of such problems are:

    • Local Businesses - these include nearby factories, industrial plants, and even small businesses such as gas stations and dry cleaners. All handle a variety of hazardous chemicals that need careful management. Spills and improper disposal of these chemicals or of industrial wastes can threaten ground water supplies.
    • Leaking Underground Tanks & Piping - petroleum products, chemicals, and wastes stored in underground storage tanks and pipes may end up in the ground water. Tanks and piping leak if they are constructed or installed improperly. Steel tanks and piping corrode with age. Tanks are often found on farms. The possibility of leaking tanks is great on old, abandoned farm sites. Farm tanks are exempt from the EPA rules for petroleum and chemical tanks.
    • Landfills and Waste Dumps - modern landfills are designed to contain any leaking liquids, but floods can carry them over the barriers. Older dumpsites may have a wide variety of pollutants that can seep into ground water.

Household Wastes - improper disposal of many common products can pollute ground water. These include cleaning solvents, used motor oil, paints, and paint thinners. Even soaps and detergents can harm drinking water. These are often a problem from faulty septic tanks and septic leaching fields.

Lead & Copper - household plumbing materials such as pipes, solder and plumbing fixtures, are the most common source of lead and copper in home drinking water. Corrosive water may cause metals in pipes or soldered joints to leach into your tap water. Your water’s acidity or alkalinity (often measured as pH) greatly affects corrosion. Temperature and mineral content also affect how corrosive it is. Lead can cause serious damage to the brain, kidneys, nervous system, and red blood cells. The age of plumbing materials, in particular, copper pipes soldered with lead, is also important. Even in relatively low amounts these metals can be harmful. EPA rules under the Safe Drinking Water Act limit lead in drinking water to 15 parts per billion. Since 1988 the Act only allows “lead free” pipe, solder, and flux in drinking water systems. The law covers both new installations and repairs of plumbing. Click here for more information on Lead in Plumbing Products.

Water Treatment Chemicals: Improper handling or storage of water-well treatment chemicals (disinfectants, corrosion inhibitors, etc.) close to your well can cause problems.

Testing Your Well Water

The quality of water from a private well is the responsibility of the well owner. Periodic testing is necessary to ensure safe and high quality drinking water and to identify the contaminants in your water that need to be reduced or the water conditions that need to be corrected. This is accomplished through water quality tests from a certified water testing laboratory. Our mail in laboratory Water Test Kits are certified in all states as an out of state testing lab. Click here for the EPA list of State Offices that provide a directory of State certified Laboratories for water quality testing. Dug and Driven wells have the greatest chance for changes to water quality because of the close proximity of the well water to the surface. Water quality in deep, drilled wells are generally stable and changes occur slowly, The US Environmental Protection Agency (EPA) has the following recommendations for testing private wells:

Before First Well Use - test for nitrates, coliform bacteria, total dissolved solids and pH levels. Consider testing your well for pesticides, organic chemicals and heavy metals.

Annually - test for nitrates, coliform bacteria, total dissolved solids and pH levels to detect contamination problems early.

More Frequent Testing - In some instances, more frequent testing than once a year may be necessary and recommended. Well water testing for bacteria should be done after any well construction activities or repairs. Here are some examples of when to consider additional well water testing:

    • If your well is located in a heavily developed area that handles hazardous chemicals
    • If your previously tested contaminant level was above state or federal standards
    • You notice a change in water quality such as taste, color or odor.
    • Someone in the household is pregnant or nursing or there are unexplained illnesses.
    • A neighbor finds a dangerous contaminant in their well water.
    • There has been a spill of chemicals or fuels near your well system.

The following chart may help you spot problems with your well water quality and indicate further water testing may be necessary:

Conditions or Nearby Activities Test Water for Contaminants
recurring gastro-intestinal illness coliform bacteria
household plumbing contains lead pH, lead, copper
radon in indoor air or region is radon rich radon
corrosion of pipes, plumbing corrosion, pH, lead
nearby areas of intensive agriculture nitrate, pesticides, coliform bacteria
coal or other mining operations nearby metals, pH, corrosion
gas drilling operations nearby chloride, sodium, barium, strontium
dump, junkyard, landfill, factory, gas station, or dry-cleaning operation nearby volatile organic compounds, total dissolved solids, pH, sulfate, chloride, metals
odor of gasoline or fuel oil, and near gas station or buried fuel tanks volatile organic compounds
objectionable taste or smell hydrogen sulfide, corrosion, metals
stained plumbing fixtures, laundry iron, copper, manganese
salty taste and seawater, or a heavily salted roadway nearby chloride, total dissolved solids, sodium
scaly residues, soaps don’t lather hardness
water appears cloudy, frothy, or colored color, detergents

Protecting Your Well Water

The EPA Safe Drinking Water Act does not protect private wells. The EPA rules only apply to "Public Drinking Water Systems", defined as systems supplying water to 25 or more people or at least 15 service connections. The risk of having a problem with your well and drinking water depends on several factors:

  • How the well is constructed.
  • Where the well is located.
  • How the well is maintained.
  • Local environment - quality of the aquifer and surrounding human activities.

The well should be constructed so rainwater flows away from it. Rainwater can pick-up harmful bacteria and chemicals on the land's surface. If this water pools near your well, it can seep into it, potentially causing health problems.

Protect your water supply by carefully managing activities near the water source. For households using a domestic well, this includes keeping contaminants away from sinkholes and the well itself. Keep hazardous chemicals out of septic systems.

  • Periodically inspect exposed parts of the well for problems such as:
    • cracked, corroded, or damaged well casing
    • broken or missing well cap
    • settling and cracking of surface seals.
  • Slope the area around the well to drain surface runoff away from the well.
  • Install a well cap or sanitary seal to prevent unauthorized use of, or entry into, the well.
  • Keep accurate records of any well maintenance, such as disinfection or sediment removal, that may require the use of chemicals in the well.
  • Hire a certified well driller for any new well construction, modification, or abandonment and closure.
  • Avoid mixing or using pesticides, fertilizers, herbicides, degreasers, fuels, and other pollutants near the well.
  • Do not dispose of wastes in dry wells or in abandoned wells.
  • Do not cut off the well casing below the land surface.
  • Pump and inspect septic systems as often as recommended by your local health department.
  • Never dispose of harsh chemicals, solvents, petroleum products, or pesticides in a septic system or dry well.

More Information

U.S. Environmental Protection Agency


The Safe Drinking Water Hotline - 800 426-4791

Ground Water Protection Council


National Environmental Services Center Drinking Water Clearinghouse


National Ground Water Association


Listing of Certified Well Contractors - 800 551-7379