1 PUBL-DG-023 2011 Wisconsin Department of Natural Resources, Bureau of Drinking Water and Groundwater Tests for Drinking Water from Private Wells Why should I test my well? As one of Wisconsin’s 900,000 private well owners or private well wa- ter consumers, you probably use groundwater for doing your family’s laundry, drinking, cooking, bathing and watering your garden. Mu- nicipalities are required to test their water supplies regularly to ensure the water is safe to drink. Since there is no requirement to test a private well except for bacteria when it is first drilled or the pump is changed, you are responsible for making sure your water is safe. Most private wells provide a clean, safe supply of water; however, contaminants can pollute private wells, and unfortunately you cannot see, smell or taste most of them. Consequently, you should test your water on a regular basis. The decision on what to test your water for should be based on the types of land uses near your well. This brochure gives information about several common contaminants found in private wells. It should help you decide when to sample your well and how often, how to find a certified laboratory and how to get more information. What tests should be done on my water? Total Coliform Bacteria and E.coli Coliform bacteria live in soil, on vegetation and in surface water. Coli- form bacteria found in the intestines of warm-blooded animals and their feces are called E.coli. Some strains of coliform bacteria can survive for long periods in soil and water and can be carried into well casings by insects. Bacteria washed into the ground by rainwater or snowmelt are usually filtered out as the water seeps through the soil, but they some- times enter water supplies through cracks in well casings, poorly-sealed caps, fractures in the underlying bedrock, and runoff into sinkholes. Coliform bacteria are the most common contaminants found in private water systems. A 1994 Wisconsin survey found them in 23% of the wells tested and E.coli in 2.4% of the wells. Most coliform bacteria do not cause illness, but indicate a breach in the water system. However, since E.coli bacteria are found in fecal material, they are often present with bacteria, viruses and parasites that can cause flu-like symptoms such as nausea, vomiting, fever and RINTED O N P CLED Y REC PAPER
2 2 diarrhea. Private wells should be tested at least once Pesticides a year for bacteria, by a laboratory that performs an E.coli test when total coliform are present. Test again Pesticides are chemicals used to control “pests” such if there is a change in the taste, color, odor or ap- as weeds and insects. Several pesticides have been pearance of your water. found in Wisconsin’s groundwater. Some of these The coliform test is one of the most important tests have entered groundwater as a result of their use on you should have done on your well water. However, farm fields. Others have been found in groundwater bacteria are only one of many possible contaminants. following spills and improper disposal. Long-term use A negative bacteria test is good news, but does not of drinking water that contains pesticide residues may mean your well is free of other contaminants. increase your risk of developing cancer or other seri- ous health problems. If your well is located within ¼ mile of a corn, Nuisance bacteria soybean or vegetable field, you should test your well water for pesticides. You should also consider a Iron and sulfur bacteria may also be present in well pesticide test if your well is within ¼ mile of an area water. Although these organisms do not pose a health where pesticides are manufactured, stored, mixed or - threat, they can affect the taste, odor and appear loaded into application equipment. Well owners who ance of water. You may have a nuisance bacteria are uncertain about the use of pesticides in their area problem if your water has a rotten egg smell or if you may also want to consider having their water tested notice slime in the toilet tank. If you suspect a nui- at least once. sance bacteria problem, try disinfecting the well and water system before testing for iron or sulfur bacteria. The most common pesticide found above health- based standards in Wisconsin’s groundwater is atra- zine, which is used to control weeds in corn crops. Nitrate An atrazine “screen,” which costs around $25, is generally a good first indicator of pesticide contami- Nitrate forms when nitrogen from fertilizers, animal nation in wells that are located near cornfields. In a wastes, septic systems, municipal sewage sludge, 2007 random survey of Wisconsin domestic wells, decaying plants and other sources combines with 12% had atrazine present and 1% had atrazine oxygenated water. above the drinking water standard. In infants under six months of age, nitrate exposure Well owners who want their wells tested for other can cause a serious condition called methemoglobin- pesticides should consider a more comprehensive emia or “blue-baby syndrome.” Infants with this con- test. Although a comprehensive pesticide test is more dition need immediate medical care because it can expensive than a “screen,” it is also more accurate lead to coma and death. Nitrate taken in by pregnant and is able to detect other pesticides if they are pres- women may reduce the amount of oxygen available ent. to the growing fetus. Test for nitrate if a pregnant woman or infant will be drinking the water. Everyone should have their water tested for nitrate Lead at least once. If you live in an area within ¼ mile of a Lead was a component of plumbing solder that was corn, soybean or vegetable field, you should test your used in homes with copper plumbing installed before water for nitrate regularly. Well owners should also 1985. It has also been used in brass fixtures. When test for nitrate regularly if their well is located near an water is naturally soft or acidic, lead can leach from area where fertilizers are manufactured or handled; solder or brass into drinking water. Wells located or an animal feed lot or manure-storage area. In gen- near existing or former cherry orchards in Door eral, shallow wells and wells with short or cracked County may also contain lead, due to historical use of casings have the highest risk of contamination; lead arsenate pesticides. however, deep wells are also at risk in some areas. A 2007 random survey of Wisconsin domestic wells Chronic exposure to lead can damage the brain, found nitrate above the 10 parts per million (ppm) kidneys, nervous system, and red blood cells. Pre- standard in 14% of the wells. Forty-eight percent had school-aged children are particularly sensitive to the nitrate above 2 ppm. toxic effects of lead. Exposure during pregnancy can affect the developing fetus.
3 3 PCBs Copper Copper is present in plumbing lines in most house- PCBs (polychlorinated biphenyls) are suspected cancer-causing agents that were manufactured and holds. Homes that have new copper plumbing or a used between 1930 and 1979. Some submersible naturally soft water supply are more likely to have well pumps that were built before 1979 contain PCB- copper-contaminated water. Symptoms caused by excessive copper exposure include stomach upsets, containing oils and have the potential to release PCBs and contaminate drinking water supplies if they fail. abdominal cramping, diarrhea and headaches. Because copper is also very toxic to fish, avoid using If your well has a submersible pump that was water containing high levels of copper to fill aquari- installed before 1979, you should contact a licensed ums. pump installer to help you determine whether it contains PCBs. If you notice an oily sheen or petro- leum odor in the water, switch to an alternate, safe Lead and Copper Testing source of drinking water and call a pump installer for assistance. Testing for lead and copper should be done on “first draw” water that has been stagnant in the distribu- tion pipes for at least six hours. If lead and copper Minerals and radioactivity levels are high due to plumbing, they can usually be reduced to acceptable levels by flushing the faucet for In some regions of Wisconsin, groundwater contains a minute or two before collecting water for drinking. high levels of toxic minerals and radioactivity. The This method is not effective in large buildings and location and depth of your well determine its suscepti- when the source of the lead or copper is distribution bility to these contaminants. lines located outside the home. Arsenic Solvents, gasoline, and fuel oil Arsenic occurs at low levels in soil and bedrock, Household and industrial solvents, gasoline and fuel but has been found at levels above drinking water oil are examples of volatile organic chemicals or standards in wells in all areas of the state, especially VOCs. Some VOCs are relatively non-toxic, while oth- in northeastern Wisconsin. Arsenic also may occur in ers can cause cancer, birth defects and reproductive wells near landfills that received paint or electronic problems. components. Exposure to arsenic at high levels can Fuel oil and gasoline can enter groundwater as result in nervous and digestive system problems. Long- term exposure to arsenic has been linked to skin and a result of a leaking storage tank or spill. Wells that are located within ¼ mile of an active or abandoned other cancers. gasoline station, home or farm fuel tank or bulk stor - Because arsenic has been found in wells across the age tank have about a 25% chance of being contam- state in various geologic formations, and the test is inated and should be tested at least once for pVOCs relatively cheap, every well owner should have their (VOCs from petroleum products). water tested at least once for arsenic. Paint thinners, dry cleaning chemicals and in- dustrial solvents can enter groundwater from spills, Radium improper disposal, leaking storage tanks and land- fills. Wells that are located within ¼ mile of a landfill, Radium is a radioactive element found in soil and dry cleaner, auto repair shop or industrial site where bedrock that can be released into groundwater. Ra- solvents have been used should be tested for VOCs. dium levels above the drinking water standard have Because solvents, gasoline and fuel oil are common been detected in eastern and west central Wisconsin in our environment, all owners of private wells should where wells draw water from deep sandstone for - consider having their water tested for VOCs at least mations, and in a few areas of northern Wisconsin once. where wells are constructed into granite. Exposure to If you notice a solvent-like or gasoline taste or high levels of radium over a period of several years odor in your water, you should use an alternate, can increase your risk of developing bone cancer. safe source of drinking water until your water can be Consult DNR on whether to test for radium. tested for VOCs.
4 4 If you live in a newer, energy-efficient home or Boron have a floor in your basement or crawl space that is dirt or is not completely sealed, you should test the Boron is often present in groundwater and foods at air in your home. Because only a small portion of the low levels. High levels of boron can enter groundwa- radon gas found in a home comes from the water ter from landfills or other sites where fly ash has been supply, it is not necessary to test your water unless deposited. Long-term exposure to boron can cause other remedies fail to reduce radon levels in the air. reproductive and developmental problems. Wells located within ¼ mile of a fly ash landfill should be tested for boron. Fluoride Water consumed by infants and preschool-aged Radon children should be tested for fluoride. Discuss your test result with your child’s doctor or dentist to decide Radon is a colorless, odorless soil gas that can enter whether he/she needs fluoride supplements. You may homes through cracks in the foundation. Radon can be advised to switch to an alternate source of water also be present in groundwater and may escape into for drinking if the fluoride concentration exceeds 4 your home from your water supply. Deep bedrock parts per million. wells are more susceptible. Breathing air that contains radon can significantly increase your chance of devel- oping lung cancer. How can I have my well tested? Sample Collection Laboratories Use a certified laboratory to test your drinking water Water collection procedures vary depending on the for possible contaminants. Labs that test for bacteria type of test being done. Samples for some tests can in water are certified by the Wisconsin Department of be collected easily, while others may require a drink- Agriculture, Trade and Consumer Protection (DATCP) ing water professional to collect the sample. For a dnr.wi.gov/org/water/dwg/ and can be found online at: reliable test result, follow the laboratory instructions . Labs that test for contaminants such exactly. PrivateLabs.pdf as nitrate, pesticides, metals, and VOCs are certified by the Wisconsin Department of Natural Resources Home Water Testing Kits dnr. (DNR) and can be found online at: online at: . Laboratories wi.gov/org/es/science/lc/PW/Lablists.htm “Do-it-yourself” drinking water test kits are avail- are also listed in the business pages of your tele- able from building supply, hardware, and discount phone directory under “Laboratories – Testing.” stores. However, there is no kit that can fully evaluate When you call a laboratory, ask if the lab is the safety of drinking water. Many kits only inform certified for the test you want. When your test has whether or not a substance is present above drinking been completed, the laboratory will send you the water standards, without providing the concentration. results directly. If a Wisconsin Unique Well Number Other kits only detect a narrow range of compounds, (WUWN) has been assigned to your well, you may while missing others. Well owners should check expi- choose to have a copy of your test results stored in a ration dates, ask questions about the sensitivity and permanent file for your well by writing the WUWN accuracy of the test kit, and follow up with a test by a on the lab form and checking the box “send copy of certified laboratory. Home water testing kits may be results to DNR.” Results of water quality tests done a useful first step, but rely on certified laboratories for by the State Laboratory of Hygiene are automatically complete peace of mind. reported to DNR for filing. You can find your Unique Well Number close to the sampling faucet on the water pipe entering the building from the well or on the main electrical fuse box.
5 5 Private Well Testing Recommendations Which wells or homes How often Contaminant should I test? should be tested? Test once every year, or when there is a Every well Coliform Bacteria change in taste, color or odor Two tests spaced six months apart Nitrate All newly-constructed wells or wells with no testing history Wells within ¼ mile of fertilized Test annually fields or animal feed lots Wells used by pregnant women Test before pregnancy and infants and at time of birth Wells that had levels close to 10 ppm Test annually Pesticides Wells within ¼ mile of agricultural Test once every 5–10 years fields, or pesticide manufacturing, storage or mixing facilities Lead Homes with copper plumbing Consider one time test installed before 1985 or brass fixtures; and naturally-soft water Wells near Door County cherry Consider one time test orchards Water used to prepare infant Test before and after flushing the faucet Copper formula or if any resident in-home for 2 to 3 minutes experiences repeated symptoms of nausea, diarrhea or abdominal Homes with new copper plumbing cramps. Homes most at risk have should be retested in 6 months new copper plumbing or naturally-soft water. Wells within ¼ mile of a landfill, Test once every 5–10 years or when VOCs (solvents, gasoline solvent or gasoline taste or odor is underground fuel or gasoline tank or fuel oil) and wells within ¼ mile of where noticed solvents have been used (Drycleaner, automotive garage or body shop, etc) Test once if needed PCBs Water with an oily sheen or petroleum odor, and submersible pump installed before 1979 Arsenic Every well Test once Test annually if arsenic is present Retest if iron levels increase or if water changes in taste or odor Radium Wells in specific areas of Wisconsin Consult with DNR or UW Extension on whether to test Boron Wells within ¼ mile of fly ash landfill Test once every 5–10 years Radon Homes with high radon levels in the Test once if needed air that are not reduced by sealing basement cracks and ventilation Fluoride Wells used by infants and preschool- Test when infant is born aged children
6 6 Topics and Contacts How can I get more Interpreting Test Results ✔ ❐ Certified laboratories information? ❐ DNR website The following DNR brochures can provide you with more information. They are available from DNR of- ❐ UW Extension website fices and may be available from: county Extension County health departments ❐ offices; local sanitary, zoning or health department Wisconsin Division of Public Health ❐ offices; or from licensed well drillers and pump install- Pesticides ✔ ers. They are also available on the DNR website at: dnr.wi.gov/org/water/dwg/priwelltp. ❐ Wisconsin Department of Agriculture, Trade and Consumer Protection Wisconsin Division of Public Health ❐ Arsenic in Drinking Water Pump Installation ✔ Bacteriological Contamination ❐ Licensed pump installers of Drinking Water ❐ Licensed well drillers Copper in Drinking Water ✔ Radon Earwigs in Your Well Wisconsin Radiation Protection Council ❐ Iron in Drinking Water ❐ Wisconsin Division of Public Health Iron Bacteria Problems in Wells ✔ Water Treatment Options Lead in Drinking Water ❐ Licensed plumbers Nitrate in Drinking Water Wisconsin Department of Commerce ❐ Pesticides in Drinking Water ✔ Bottled water quality Radium in Drinking Water ❐ Wisconsin Department of Agriculture, Trade Radon in Drinking Water and Consumer Protection Restoring Drinking Water—State Funds for Replacing Contaminated Wells This brochure was revised by the Wisconsin Department Sulfur Bacteria Problems in Wells of Natural Resources with assistance from the Education Subcommittee of the Groundwater Coordinating Council. Volatile Organic Chemicals in Drinking Water The Wisconsin Department of Natural Resources provides equal opportunity in its employment, programs, services UW Extension has several drinking water brochures and functions under an Affirmative Action Plan. If you have any questions, please write to: Equal Opportunity Office, uwsp.edu/cnr/gndwater/privatewells. available at: Department of the Interior, Washington, D.C. 20240. index . Click on “Water Quality” under the “Natural This publication is available in alternative format (large Resources” drop-down menu. print, Braille, audio tape, etc) upon request. Please call (608) 266-0821 for more information.