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Water: Private Wells

Frequent Questions

How can I test the quality of my private drinking water supply? 

Consider testing your well for pesticides, organic chemicals, and heavy metals before you use it for the first time. Test private water supplies annually for nitrate and coliform bacteria to detect contamination problems early. Test them more frequently if you suspect a problem. Be aware of activities in your watershed that may affect the water quality of your well, especially if you live in an unsewered area.

Reasons to Test Your Water

  • The chart below will help you spot problems. The last five problems listed are not an immediate health concern, but they can make your water taste bad, may indicate problems, and could affect your well long term.

    Conditions or Nearby Activities: Test for:
    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
    Rapid wear of water treatment equipment pH, corrosion
    Water softener needed to treat hardness Manganese, iron
    Water appears cloudy, frothy, or colored Color, detergents
  • You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.

    For more information on for more information on what human activities can polluteground water see:

    If you use a private laboratory to conduct the testing, nitrate and bacteria samples will typically cost between $10 and $20 to complete. Testing for other contaminants will be more expensive. For example, testing for pesticides or organic chemicals may cost from several hundred to several thousand dollars. Only use laboratories that are certified to do drinking water tests. To find a certified laboratory in your state, you can contact:

    • A State Certification Officer to get a list of certified water testing labs in your state, or
    • Your local health department may also test private well water for free. Phone numbers for your local, county, or state health department are available under the "health" or "government" listings in your phone book.

    Most laboratories mail back the sample results within a week or two. If a contaminant is detected, the results will include the concentration found and an indication of whether this level exceeds a drinking water health standard.

    If a standard is exceeded in your sample, retest the water supply immediately and contact your public health department for assistance. Some problems can be handled quickly. For example, high bacteria concentrations can sometimes be controlled by disinfecting a well. Filters or other on-site treatment processes may also remove some contaminants. Other problems may require a new source of water, or a new, deeper well. If serious problems persist, you may need to rely on bottled water until a new water source can be obtained.

    You should test private water supplies annually for nitrates,coliform bacteria, total dissolved solids, and pH levels to detect contamination problems early. Test more frequently if a problem was found in earlier tests.

    For more information, read Home Water Testing PDF (2pp, 564K)

    What concerns should I have after a flood if I have a private well?

    Stay away from the well pump while flooded to avoid electric shock, AND . . .

    • Do not drink or wash from the flooded well to avoid becoming sick.
    • Get assistance from a well or pump contractor to clean and turn on the pump.
    • After the pump is turned back on, pump the well until the water runs clear to rid the well of flood water.
    • If the water does not run clear, get advice from the county or state health department or extension service.

    For additional information:

    How can I protect my private water supply?

    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.
    • Have the well tested once a year for coliform bacteria, nitrates, and other constituents of concern.
    • 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.

    For more information on protecting your well visit these web sites:

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