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PRINTED ON RECYCLED PAPER Wisconsin Department of Natural Resources, Bureau of Drinking Water and Groundwater PUBL-DG-023 2007 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 fi rst 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 fi nd a certifi ed 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 fi ltered 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 fl u-like such as nausea, vomiting, fever and ---PAGE BREAK--- 2 diarrhea. Private wells should be tested at least once a year for bacteria, by a laboratory that performs an E.coli test when total coliform are present. Test again if there is a change in the taste, color, odor or ap- pearance of your water. The coliform test is one of the most important tests you should have done on your well water. However, bacteria are only one of many possible contaminants. A negative bacteria test is good news, but does not mean your well is free of other contaminants. Nuisance bacteria Iron and sulfur bacteria may also be present in well water. Although these organisms do not pose a health threat, they can affect the taste, odor and appear- ance of water. You may have a nuisance bacteria problem if your water has a rotten egg smell or if you notice slime in the toilet tank. If you suspect a nui- sance bacteria problem, try disinfecting the well and water system before testing for iron or sulfur bacteria. Nitrate Nitrate forms when nitrogen from fertilizers, animal wastes, septic systems, municipal sewage sludge, decaying plants and other sources combines with oxygenated water. In infants under six months of age, nitrate exposure can cause a serious condition called methemoglobin- emia or “blue-baby Infants with this con- dition need immediate medical care because it can lead to coma and death. Nitrate taken in by pregnant women may reduce the amount of oxygen available 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 at least once. If you live in an area within ¼ mile of a corn, soybean or vegetable fi eld, you should test your water for nitrate regularly. Well owners should also test for nitrate regularly if their well is located near an area where fertilizers are manufactured or handled; or an animal feed lot or manure-storage area. In gen- eral, shallow wells and wells with short or cracked casings have the highest risk of contamination; however, deep wells are also at risk in some areas. A 2001 random survey of Wisconsin domestic wells found nitrate above the 10 parts per million (ppm) standard in 14% of the wells. Forty-eight percent had nitrate above 2 ppm. Pesticides Pesticides are chemicals used to control “pests” such as weeds and insects. Several pesticides have been found in Wisconsin’s groundwater. Some of these have entered groundwater as a result of their use on farm fi elds. Others have been found in groundwater following spills and improper disposal. Long-term use of drinking water that contains pesticide residues may increase your risk of developing cancer or other seri- ous health problems. If your well is located within ¼ mile of a corn, soybean or vegetable fi eld, you should test your well water for pesticides. You should also consider a pesticide test if your well is within ¼ mile of an area where pesticides are manufactured, stored, mixed or loaded into application equipment. Well owners who are uncertain about the use of pesticides in their area may also want to consider having their water tested at least once. 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. An atrazine “screen,” which costs around $25, is generally a good fi rst indicator of pesticide contami- nation in wells that are located near cornfi elds. In a 2001 random survey of Wisconsin domestic wells, 12% had atrazine present and 1% had atrazine above the drinking water standard. Well owners who want their wells tested for other pesticides should consider a more comprehensive test. Although a comprehensive pesticide test is more expensive than a “screen,” it is also more accurate and is able to detect other pesticides if they are pres- ent. Lead Lead was a component of plumbing solder that was used in homes with copper plumbing installed before 1985. It has also been used in brass fi xtures. When water is naturally soft or acidic, lead can leach from solder or brass into drinking water. Wells located near existing or former cherry orchards in Door County may also contain lead, due to historical use of lead arsenate pesticides. Chronic exposure to lead can damage the brain, kidneys, nervous system, and red blood cells. Pre- school-aged children are particularly sensitive to the toxic effects of lead. Exposure during pregnancy can affect the developing fetus. ---PAGE BREAK--- 3 Copper Copper is present in plumbing lines in most house- holds. Homes that have new copper plumbing or a naturally soft water supply are more likely to have copper-contaminated water. caused by excessive copper exposure include stomach upsets, abdominal cramping, diarrhea and headaches. Because copper is also very toxic to fi sh, avoid using water containing high levels of copper to fi ll aquari- ums. Lead and Copper Testing Testing for lead and copper should be done on “fi rst draw” water that has been stagnant in the distribu- tion pipes for at least six hours. If lead and copper levels are high due to plumbing, they can usually be reduced to acceptable levels by fl ushing the faucet for a minute or two before collecting water for drinking. This method is not effective in large buildings and when the source of the lead or copper is distribution lines located outside the home. Solvents, gasoline, and fuel oil Household and industrial solvents, gasoline and fuel oil are examples of volatile organic chemicals or VOCs. Some VOCs are relatively non-toxic, while oth- ers can cause cancer, birth defects and reproductive problems. Fuel oil and gasoline can enter groundwater as a result of a leaking storage tank or spill. Wells that are located within ¼ mile of an active or abandoned gasoline station, home or farm fuel tank or bulk stor- age tank have about a 25% chance of being contam- inated and should be tested at least once for pVOCs (VOCs from petroleum products). Paint thinners, dry cleaning chemicals and in- dustrial solvents can enter groundwater from spills, improper disposal, leaking storage tanks and land- fi lls. Wells that are located within ¼ mile of a landfi ll, dry cleaner, auto repair shop or industrial site where solvents have been used should be tested for VOCs. Because solvents, gasoline and fuel oil are common in our environment, all owners of private wells should consider having their water tested for VOCs at least once. If you notice a solvent-like or gasoline taste or odor in your water, you should use an alternate, safe source of drinking water until your water can be tested for VOCs. PCBs PCBs biphenyls) are suspected cancer-causing agents that were manufactured and used between 1930 and 1979. Some submersible well pumps that were built before 1979 contain PCB- containing oils and have the potential to release PCBs and contaminate drinking water supplies if they fail. If your well has a submersible pump that was installed before 1979, you should contact a licensed 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 source of drinking water and call a pump installer for assistance. Minerals and radioactivity In some regions of Wisconsin, groundwater contains high levels of toxic minerals and radioactivity. The location and depth of your well determine its suscepti- bility to these contaminants. Arsenic Arsenic occurs at low levels in soil and bedrock, but has been found at levels above drinking water standards in wells in all areas of the state, especially in northeastern Wisconsin. Arsenic also may occur in wells near landfi lls that received paint or electronic components. Exposure to arsenic at high levels can result in nervous and digestive system problems. Long- term exposure to arsenic has been linked to skin and other cancers. Because arsenic has been found in wells across the state in various geologic formations, and the test is relatively cheap, every well owner should have their water tested at least once for arsenic. Radium Radium is a radioactive element found in soil and bedrock that can be released into groundwater. Ra- dium levels above the drinking water standard have been detected in eastern and west central Wisconsin where wells draw water from deep sandstone for- mations, and in a few areas of northern Wisconsin where wells are constructed into granite. Exposure to high levels of radium over a period of several years can increase your risk of developing bone cancer. Consult DNR on whether to test for radium. ---PAGE BREAK--- 4 Boron Boron is often present in groundwater and foods at low levels. High levels of boron can enter groundwa- ter from landfi lls or other sites where fl y ash has been deposited. Long-term exposure to boron can cause reproductive and developmental problems. Wells located within ¼ mile of a fl y ash landfi ll should be tested for boron. Radon Radon is a colorless, odorless soil gas that can enter homes through cracks in the foundation. Radon can also be present in groundwater and may escape into your home from your water supply. Deep bedrock wells are more susceptible. Breathing air that contains radon can signifi cantly increase your chance of devel- oping lung cancer. If you live in a newer, energy-effi cient home or have a fl oor in your basement or crawl space that is dirt or is not completely sealed, you should test the air in your home. Because only a small portion of the radon gas found in a home comes from the water supply, it is not necessary to test your water unless other remedies fail to reduce radon levels in the air. Fluoride Water consumed by infants and preschool-aged children should be tested for fl uoride. Discuss your test result with your child’s doctor or dentist to decide whether he/she needs fl uoride supplements. You may be advised to switch to an alternate source of water for drinking if the fl uoride concentration exceeds 4 parts per million. How can I have my well tested? Laboratories Use a certifi ed laboratory to test your drinking water for possible contaminants. Labs that test for bacteria in water are certifi ed by the Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) and can be found online at: dnr.wi.gov/org/water/dwg/ wells.htm. Labs that test for contaminants such as nitrate, pesticides, metals, and VOCs are certifi ed by the Wisconsin Department of Natural Resources (DNR) and can be found online at: online at: dnr. wi.gov/org/es/science/lc/ under the category “Certifi ed Lab Lists.” Laboratories are also listed in the business pages of your telephone directory under “Laborato- ries – Testing.” When you call a laboratory, ask if the lab is certifi ed for the test you want. When your test has been completed, the laboratory will send you the results directly. If a Wisconsin Unique Well Number (WUWN) has been assigned to your well, you may choose to have a copy of your test results stored in a permanent fi le for your well by writing the WUWN on the lab form and checking the box “send copy of results to DNR.” Results of water quality tests done by the State Laboratory of Hygiene are automatically reported to DNR for fi ling. You can fi nd 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. Sample Collection Water collection procedures vary depending on the type of test being done. Samples for some tests can be collected easily, while others may require a drink- ing water professional to collect the sample. For a reliable test result, follow the laboratory instructions exactly. Home Water Testing Kits “Do-it-yourself” drinking water test kits are avail- able from building supply, hardware, and discount stores. However, there is no kit that can fully evaluate the safety of drinking water. Many kits only inform whether or not a substance is present above drinking water standards, without providing the concentration. Other kits only detect a narrow range of compounds, while missing others. Well owners should check expi- ration dates, ask questions about the sensitivity and accuracy of the test kit, and follow up with a test by a certifi ed laboratory. Home water testing kits may be a useful fi rst step, but rely on certifi ed laboratories for complete peace of mind. ---PAGE BREAK--- 5 Private Well Testing Recommendations Contaminant Which wells or homes How often should be tested? should I test? Coliform Bacteria Every well Test once every year, or when there is a change in taste, color or odor Nitrate All newly-constructed wells or Two tests spaced six months apart wells with no testing history Wells within ¼ mile of fertilized Test annually fi elds 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 fi elds, or pesticide manufacturing, storage or mixing facilities Lead Homes with copper plumbing Consider one time test installed before 1985 or brass fi xtures; and naturally-soft water Wells near Door County cherry Consider one time test orchards Copper Water used to prepare infant Test before and after fl ushing the faucet formula or if any resident in-home for 2 to 3 minutes experiences repeated 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. VOCs Wells within ¼ mile of a landfi ll, Test once every 5–10 years or when (solvents, gasoline underground fuel or gasoline tank solvent or gasoline taste or odor is or fuel oil) and wells within ¼ mile of where noticed solvents have been used automotive garage or body shop, etc) PCBs Water with an oily sheen or Test once if needed 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 specifi c areas of Wisconsin Consult with DNR or UW Extension on whether to test Boron Wells within ¼ mile of fl y ash landfi ll 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 ---PAGE BREAK--- 6 This brochure was revised by the Wisconsin Department of Natural Resources with assistance from the Education Subcommittee of the Groundwater Coordinating Council. The Wisconsin Department of Natural Resources provides equal opportunity in its employment, programs, services and functions under an Affi rmative Action Plan. If you have any questions, please write to: Equal Opportunity Offi ce, Department of the Interior, Washington, D.C. 20240. This publication is available in alternative format (large print, Braille, audio tape, etc) upon request. Please call (608) 266-0821 for more information. Region Offi ces Northern Region 810 W. Maple Street Spooner, WI 54801 (715) 635-2101 or 107 Sutliff Avenue Rhinelander, WI 54501 (715) 365-8900 South Central Region 3911 Fish Hatchery Road Fitchburg, WI 53711 (608) 275-3266 West Central Region 1300 W. Clairemont PO Box 4001 Eau Claire, WI 54702-4001 (715) 839-3700 Southeast Region 2300 N. Dr. Martin Luther King, Jr. Drive Milwaukee, WI 53212 (414) 263-8500 Northeast Region 2984 Shawano Avenue P.O. Box 10448 Green Bay, WI 54307-0448 (920) 662-5100 Central Offi ce 101 S. Webster, P.O. Box 7921 Madison, WI 53707-7921 (608) 266-0821 How can I get more information? The following DNR brochures can provide you with more information. They are available from DNR of- fi ces and may be available from: county Extension offi ces; local sanitary, zoning or health department offi ces; or from licensed well drillers and pump install- ers. They are also available on the DNR website at: dnr.wi.gov/org/water/dwg/priwelltp. Topics and Contacts ✔ Interpreting Test Results ❐ Certifi ed laboratories ❐ DNR website ❐ UW Extension website ❐ County health departments ❐ Wisconsin Division of Public Health ✔ Pesticides ❐ Wisconsin Department of Agriculture, Trade and Consumer Protection ❐ Wisconsin Division of Public Health ✔ Pump Installation ❐ Licensed pump installers ❐ Licensed well drillers ✔ Radon ❐ Wisconsin Radiation Protection Council ❐ Wisconsin Division of Public Health ✔ Water Treatment Options ❐ Licensed plumbers ❐ Wisconsin Department of Commerce ✔ Bottled water quality ❐ Wisconsin Department of Agriculture, Trade and Consumer Protection Arsenic in Drinking Water Bacteriological Contamination of Drinking Water Copper in Drinking Water Earwigs in Your Well Iron in Drinking Water Iron Bacteria Problems in Wells Lead in Drinking Water Nitrate in Drinking Water Pesticides in Drinking Water Radium in Drinking Water Radon in Drinking Water Restoring Drinking Water—State Funds for Replacing Contaminated Wells Sulfur Bacteria Problems in Wells Volatile Organic Chemicals in Drinking Water UW Extension has several drinking water brochures available at: uwsp.edu/cnr/gndwater/privatewells. index. 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