EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions Private Drinking Water Wells Recent Additions | Contact Us | Print Version Search: EPA Home > Water > Safewater Home > Private Drinking Water Wells > Frequent Questions Safewater Home Private Drinking Water Wells Home Basic Information Where You Live Frequent Questions Human Health Partnerships What You Can Do Publications Related Links Frequent Questions G How can I test the quality of my private drinking water supply? G What concerns should I have after a flood if I have a private well? G How can I protect my private water supply? 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 http://www.epa.gov/safewater/privatewells/faq.html (1 of 6)9/14/2009 1:33:14 PM EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions 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 http://www.epa.gov/safewater/privatewells/faq.html (2 of 6)9/14/2009 1:33:14 PM EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions 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 For more information on for more information on what human activities can pollute ground water see: G Drinking Water From Household Wells PDF (24 pp, 1 M) (ALL ABOUT PDF FILES) EPA 816-K-02-003 January 2002 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: H A State Certification Officer to get a list of certified water testing labs in your state (epa.gov/safewater/privatewells/labs. html), or H 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. H See the List of Drinking Water Contaminants and their http://www.epa.gov/safewater/privatewells/faq.html (3 of 6)9/14/2009 1:33:14 PM EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions Maximum Contaminant Levels (MCL) page for information on Drinking Water Contaminants. 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 (564 K PDF FILE, 2pgs) (ALL ABOUT PDF FILES) 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 . . . H Do not drink or wash from the flooded well to avoid becoming sick. H Get assistance from a well or pump contractor to clean and turn on the pump. H After the pump is turned back on, pump the well until the water runs clear to rid the well of flood water. H If the water does not run clear, get advice from the county or state health department or extension service. For additional information: H What to Do After the Flood H Septic Systems — What to Do after the Flood H After a Hurricane or Flood: Cleanup of Flood Water - From the Center for Disease Control How can I protect my private water supply? http://www.epa.gov/safewater/privatewells/faq.html (4 of 6)9/14/2009 1:33:14 PM EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions 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. H Periodically inspect exposed parts of the well for problems such as: I cracked, corroded, or damaged well casing I broken or missing well cap I settling and cracking of surface seals. H Slope the area around the well to drain surface runoff away from the well. H Install a well cap or sanitary seal to prevent unauthorized use of, or entry into, the well. H Have the well tested once a year for coliform bacteria, nitrates, and other constituents of concern. H Keep accurate records of any well maintenance, such as disinfection or sediment removal, that may require the use of chemicals in the well. H Hire a certified well driller for any new well construction, modification, or abandonment and closure. H Avoid mixing or using pesticides, fertilizers, herbicides, degreasers, fuels, and other pollutants near the well. H Do not dispose of wastes in dry wells or in abandoned wells. H Do not cut off the well casing below the land surface. H Pump and inspect septic systems as often as recommended by your local health department. H 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: H National Ground Water Association H American Ground Water Trust Safewater Home | Safe Drinking Water Hotline | Glossary | Water Publications http://www.epa.gov/safewater/privatewells/faq.html (5 of 6)9/14/2009 1:33:14 PM EPA > Water > Safewater > Private Drinking Water Wells > Frequent Questions EPA Home | Privacy and Security Notice | Contact Us Last updated on undefined, undefined NaNth, NaN URL: http://www.epa.gov/safewater/privatewells/faq.html http://www.epa.gov/safewater/privatewells/faq.html (6 of 6)9/14/2009 1:33:14 PM Drinking Water Contaminants | Safewater| Water | US EPA Jump to main content. Drinking Water Contaminants Recent Additions | Contact Us Search: All EPA This Area G You are here: EPA Home G Water G Safewater G Drinking Water Contaminants On this page G National Primary Drinking Water Regulations H List of Drinking Water Contaminants & their MCLs G National Secondary Drinking Water Regulations H List of Secondary Drinking Water Regulations G Unregulated Contaminants National Primary Drinking Water Regulations National Primary Drinking Water Regulations (NPDWRs or primary standards) are legally enforceable standards that apply to public water systems. Primary standards protect public health by limiting the http://www.epa.gov/safewater/contaminants/index.html (1 of 19)9/14/2009 1:34:08 PM Go Drinking Water Contaminants | Safewater| Water | US EPA levels of contaminants in drinking water. Visit the list of regulated contaminants with links for more details. G List of Contaminants & their Maximum Contaminant Level (MCLs) G Setting Standards for Safe Drinking Water to learn about EPA's standard-setting process G EPA's Regulated Contaminant Timeline (PDF) (1 pp, 86 K ) (About PDF) G National Primary Drinking Water Regulations- The complete regulations regarding these contaminants availible from the Code of Federal Regulations Website Information on this section G Alphabetical List (PDF) (6 pp, 924 K) (About PDF) EPA 816-F-09-0004, May 2009 G The links provided below are to either Consumer Fact Sheet, Rule Implementation web sites, or PDF files. (About PDF) List of Contaminants & their MCLs G Microorganisms G Disinfectants G Disinfection Byproducts G Inorganic Chemicals G Organic Chemicals G Radionuclides Microorganisms Contaminant MCLG1 (mg/L)2 MCL or TT1 (mg/ L)2 Potential Health Effects from Ingestion of Water Sources of Contaminant in Drinking Water Cryptosporidium (pdf file) zero TT 3 Gastrointestinal illness (e.g., diarrhea, vomiting, cramps) Human and animal fecal waste http://www.epa.gov/safewater/contaminants/index.html (2 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Giardia lamblia zero TT3 Gastrointestinal illness (e.g., diarrhea, vomiting, cramps) Human and animal fecal waste Heterotrophic plate count n/a TT3 HPC has no health effects; it is an analytic method used to measure the variety of bacteria that are common in water. The lower the concentration of bacteria in drinking water, the better maintained the water system is. HPC measures a range of bacteria that are naturally present in the environment Legionella zero TT3 Legionnaire's Disease, a type of pneumonia Found naturally in water; multiplies in heating systems Total Coliforms (including fecal coliform and E. Coli) zero 5.0%4 Not a health threat in itself; it is used to indicate whether other potentially harmful bacteria may be present5 Coliforms are naturally present in the environment; as well as feces; fecal coliforms and E. coli only come from human and animal fecal waste. Turbidity n/a TT3 Turbidity is a measure of the cloudiness of water. It is used to indicate water quality and filtration effectiveness (e.g., whether disease-causing organisms are present). Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria. These organisms can cause symptoms such as nausea, cramps, diarrhea, and associated headaches. Soil runoff Viruses (enteric) zero TT3 Gastrointestinal illness (e.g., diarrhea, vomiting, cramps) Human and animal fecal waste http://www.epa.gov/safewater/contaminants/index.html (3 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Top of page Disinfection Byproducts Contaminant MCLG1 (mg/L)2 MCL or TT1 (mg/ L)2 Potential Health Effects from Ingestion of Water Sources of Contaminant in Drinking Water Bromate zero 0.010 Increased risk of cancer Byproduct of drinking water disinfection Chlorite 0.8 1.0 Anemia; infants & young children: nervous system effects Byproduct of drinking water disinfection Haloacetic acids (HAA5) n/a6 0.0607 Increased risk of cancer Byproduct of drinking water disinfection Total Trihalomethanes (TTHMs) n/a6 0.0807 Liver, kidney or central nervous system problems; increased risk of cancer Byproduct of drinking water disinfection Top of page Disinfectants Contaminant MRDLG1 (mg/L)2 MRDL1 (mg/L)2 Potential Health Effects from Ingestion of Water Sources of Contaminant in Drinking Water Chloramines (as Cl2) MRDLG=41 MRDL=4.01 Eye/nose irritation; stomach discomfort, anemia Water additive used to control microbes Chlorine (as Cl2) MRDLG=41 MRDL=4.01 Eye/nose irritation; stomach discomfort Water additive used to control microbes http://www.epa.gov/safewater/contaminants/index.html (4 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Chlorine dioxide (as ClO2) MRDLG=0.81 MRDL=0.81 Anemia; infants & young children: nervous system effects Water additive used to control microbes Top of page Inorganic Chemicals Contaminant MCLG1 (mg/L)2 MCL or TT1 (mg/L)2 Potential Health Effects from Ingestion of Water Sources of Contaminant in Drinking Water Antimony 0.006 0.006 Increase in blood cholesterol; decrease in blood sugar Discharge from petroleum refineries; fire retardants; ceramics; electronics; solder Arsenic 07 0.010 as of 01/23/06 Skin damage or problems with circulatory systems, and may have increased risk of getting cancer Erosion of natural deposits; runoff from orchards, runoff from glass & electronicsproduction wastes Asbestos (fiber >10 micrometers) 7 million fibers per liter 7 MFL Increased risk of developing benign intestinal polyps Decay of asbestos cement in water mains; erosion of natural deposits Barium 2 2 Increase in blood pressure Discharge of drilling wastes; discharge from metal refineries; erosion of natural deposits Beryllium 0.004 0.004 Intestinal lesions Discharge from metal refineries and coal- burning factories; discharge from electrical, aerospace, and defense industries http://www.epa.gov/safewater/contaminants/index.html (5 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Cadmium 0.005 0.005 Kidney damage Corrosion of galvanized pipes; erosion of natural deposits; discharge from metal refineries; runoff from waste batteries and paints Chromium (total) 0.1 0.1 Allergic dermatitis Discharge from steel and pulp mills; erosion of natural deposits Copper 1.3 TT8; Action Level=1.3 Short term exposure: Gastrointestinal distress Long term exposure: Liver or kidney damage People with Wilson's Disease should consult their personal doctor if the amount of copper in their water exceeds the action level Corrosion of household plumbing systems; erosion of natural deposits Cyanide (as free cyanide) 0.2 0.2 Nerve damage or thyroid problems Discharge from steel/ metal factories; discharge from plastic and fertilizer factories Fluoride 4.0 4.0 Bone disease (pain and tenderness of the bones); Children may get mottled teeth Water additive which promotes strong teeth; erosion of natural deposits; discharge from fertilizer and aluminum factories http://www.epa.gov/safewater/contaminants/index.html (6 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Lead zero TT8; Action Level=0.015 Infants and children: Delays in physical or mental development; children could show slight deficits in attention span and learning abilities Adults: Kidney problems; high blood pressure Corrosion of household plumbing systems; erosion of natural deposits Mercury (inorganic) 0.002 0.002 Kidney damage Erosion of natural deposits; discharge from refineries and factories; runoff from landfills and croplands Nitrate (measured as Nitrogen) 10 10 Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits Nitrite (measured as Nitrogen) 1 1 Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome. Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits Selenium 0.05 0.05 Hair or fingernail loss; numbness in fingers or toes; circulatory problems Discharge from petroleum refineries; erosion of natural deposits; discharge from mines http://www.epa.gov/safewater/contaminants/index.html (7 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Thallium 0.0005 0.002 Hair loss; changes in blood; kidney, intestine, or liver problems Leaching from ore- processing sites; discharge from electronics, glass, and drug factories Top of page Organic Chemicals Contaminant MCLG1 (mg/L)2 MCL or TT1 (mg/L)2 Potential Health Effects from Ingestion of Water Sources of Contaminant in Drinking Water Acrylamide zero TT9 Nervous system or blood problems; increased risk of cancer Added to water during sewage/ wastewater treatment Alachlor zero 0.002 Eye, liver, kidney or spleen problems; anemia; increased risk of cancer Runoff from herbicide used on row crops Atrazine 0.003 0.003 Cardiovascular system or reproductive problems Runoff from herbicide used on row crops Benzene zero 0.005 Anemia; decrease in blood platelets; increased risk of cancer Discharge from factories; leaching from gas storage tanks and landfills Benzo(a)pyrene (PAHs) zero 0.0002 Reproductive difficulties; increased risk of cancer Leaching from linings of water storage tanks and distribution lines Carbofuran 0.04 0.04 Problems with blood, nervous system, or reproductive system Leaching of soil fumigant used on rice and alfalfa http://www.epa.gov/safewater/contaminants/index.html (8 of 19)9/14/2009 1:34:08 PM Drinking Water Contaminants | Safewater| Water | US EPA Carbon tetrachloride zero 0.005 Liver problems; increased risk of cancer Discharge from chemical plants and other industrial activities Chlordane zero 0.002 Liver or nervous system problems; increased risk of cancer Residue of banned termiticide Chlorobenzene 0.1 0.1 Liver or kidney problems Discharge from chemical and agricultural chemical factories 2,4-D 0.07 0.07 Kidney, liver, or adrenal gland problems Runoff from herbicide used on row crops Dalapon 0.2 0.2 Minor kidney changes Runoff from herbicide used on rights of way 1,2-Dibromo-3- chloropropane (DBCP) zero 0.0002 Reproductive difficulties; increased risk of cancer Runoff/leaching from soil fumigant used on soybeans, cotton, pineapples, and orchards o-Dichlorobenzene 0.6 0.6 Liver, kidney, or circulatory system problems Discharge from industrial chemical factories p-Dichlorobenzene 0.075 0.075 Anemia; liver, kidney or spleen damage; changes in blood Discharge from industrial chemical factories 1,2-Dichloroethane zero 0.005 Increased risk of cancer Discharge from industrial chemical factories http://www.epa.gov/safewater/contaminants/index.html (9 of 19)9/14/2009 1:34:08 PM