What to test your well for

Total coliform and E. coli bacteria

The Minnesota Department of Health explains that total coliform bacteria are an indicator: if found, surface contamination may have reached the water and germs may be present. Minnesota Department of Health

• Routine yearly check EPA says to test a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH, and to test for other contaminants you suspect. U.S. EPA
• A new baby, or one on the way The Minnesota Department of Health says germs signalled by coliform can cause diarrhea, vomiting, cramps, nausea and fever, and are most dangerous for infants, children, the elderly and people with weak immune systems. Minnesota Department of Health
• Someone pregnant or nursing, small children or older adults at home EPA suggests testing more often if small children or elderly adults live in the home, or if someone is pregnant or nursing. U.S. EPA
• Near crop fields, feedlots or livestock EPA lists fertilizer storage and use, animal feedlots, manure and pesticide storage and use among the farm sources that can contaminate a private well. U.S. EPA
• A septic system on the property or next door EPA says effluent from septic leach fields can reach a water source and put germs into a well. U.S. EPA
• The water changed: taste, smell or colour EPA also says to test immediately when you notice a change in the water, such as its odor, color or taste. U.S. EPA
• A rotten egg smell The Minnesota Department of Health says the rotten egg smell usually is not a safety problem, but rarely it comes from sewage, so it advises a coliform bacteria and nitrate test to be safe. Minnesota Department of Health
• Buying or selling the home FHA requires a well water test for new construction, when the appraiser reports well or water problems, when water is known or reported unsafe, or near dumps, landfills, industrial sites or farms. HUD Handbook 4000.1 (FHA)
• Buying or selling the home For FHA, the sample must be collected and transported by a disinterested third party, such as the health authority or a lab, never the buyer or owner. HUD Handbook 4000.1 (FHA)
• Floodwater reached the well Texas A&M AgriLife Extension says to assume a flooded well is contaminated until it has been disinfected and tested. Texas A&M AgriLife Extension
• Floodwater reached the well EPA advises having the water tested for bacteria 7 to 10 days after disinfection, and warns a flooded area well may not be safe for months. U.S. EPA
• The pump, pipes or well were just repaired EPA says to test immediately after you replace or repair any part of the well system, or after flooding, land disturbance or new construction nearby. U.S. EPA
• The pump, pipes or well were just repaired DEQ says testing is especially important after pipes, the pressure tank, the pump or the well casing have been replaced or repaired. Oklahoma DEQ
• Near a gas station, landfill, oil or gas wells, or a pipeline The FHA appraiser must require a test or inspection in cases such as nearby intensive farming, a nearby gas station or landfill, or water with an unusually objectionable taste, smell or appearance. HUD Handbook 4000.1 (FHA)

Nitrate

EPA's drinking water limit (MCL) for nitrate is 10 milligrams per liter, measured as nitrogen. Infants under six months who drink water above it could become seriously ill. U.S. EPA

• Routine yearly check EPA says to test a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH, and to test for other contaminants you suspect. U.S. EPA
• A new baby, or one on the way The Minnesota Department of Health advises testing your well before bringing a new baby home. Minnesota Department of Health
• A new baby, or one on the way The Minnesota Department of Health says bottle-fed babies under six months old are at the highest risk. Minnesota Department of Health
• A new baby, or one on the way The Minnesota Department of Health warns that boiling does not make high-nitrate water safe; it concentrates the nitrate. Use a safe source such as bottled water for formula. Minnesota Department of Health
• Someone pregnant or nursing, small children or older adults at home EPA suggests testing more often if small children or elderly adults live in the home, or if someone is pregnant or nursing. U.S. EPA
• Near crop fields, feedlots or livestock EPA lists chemical fertilizers, human sewage and animal waste as nitrate sources that can reach a private well. U.S. EPA
• A septic system on the property or next door EPA lists chemical fertilizers, human sewage and animal waste as nitrate sources that can reach a private well. U.S. EPA
• The water changed: taste, smell or colour EPA also says to test immediately when you notice a change in the water, such as its odor, color or taste. U.S. EPA
• A rotten egg smell The Minnesota Department of Health says the rotten egg smell usually is not a safety problem, but rarely it comes from sewage, so it advises a coliform bacteria and nitrate test to be safe. Minnesota Department of Health
• Buying or selling the home The Oklahoma DEQ State Environmental Laboratory charges a base fee of $104 for its daycare/real estate test list (coliform and E. coli, nitrate, nitrite, lead). Oklahoma DEQ

Total dissolved solids and pH

• Routine yearly check EPA says to test a private well every year for total coliform bacteria, nitrates, total dissolved solids and pH, and to test for other contaminants you suspect. U.S. EPA
• Red, brown or black stains on fixtures or laundry The Minnesota Department of Health says yellow or red water usually means iron, but only a lab test gives the exact amount needed to pick a treatment; it also suggests testing hardness, pH, alkalinity and iron bacteria. Minnesota Department of Health

Arsenic

EPA's drinking water limit for arsenic is 0.010 milligrams per liter (10 micrograms per liter), in force since January 23, 2006; long term exposure is linked to skin damage, circulation problems and a higher cancer risk. U.S. EPA

• Central Oklahoma (Garber-Wellington aquifer) The Oklahoma DEQ says arsenic, chromium, selenium and uranium in parts of the Garber Wellington (Central Oklahoma) aquifer sometimes exceed federal drinking water limits. Oklahoma DEQ
• Central Oklahoma (Garber-Wellington aquifer) Oklahoma DEQ says high levels turn up in both shallow and deep wells anywhere in that aquifer, so the risk is unknown until the water is tested. Oklahoma DEQ
• West Texas, the southern High Plains or South Texas Texas A&M AgriLife Extension reports naturally high arsenic in the southern High Plains (Ogallala aquifer), several West Texas counties and South Texas (Gulf Coast aquifer). Texas A&M AgriLife Extension
• Drought, or the water level is dropping Texas A&M AgriLife Extension says falling water levels let air into the aquifer, so a well with some arsenic should expect higher levels during a drought; test during and after. Texas A&M AgriLife Extension

Lead

Texas A&M AgriLife Extension says lead rarely occurs naturally in well water; it usually comes from corroding pipes, solder and brass fixtures, and lead pipes are most likely in homes built before 1930. Texas A&M AgriLife Extension

• Someone pregnant or nursing, small children or older adults at home EPA lists delays in physical or mental development as a risk of lead for infants and children. U.S. EPA
• Buying or selling the home The Oklahoma DEQ State Environmental Laboratory charges a base fee of $104 for its daycare/real estate test list (coliform and E. coli, nitrate, nitrite, lead). Oklahoma DEQ
• An older home or old plumbing Texas A&M AgriLife Extension says lead rarely occurs naturally in well water; it usually comes from corroding pipes, solder and brass fixtures, and lead pipes are most likely in homes built before 1930. Texas A&M AgriLife Extension
• An older home or old plumbing For a lead test, Texas A&M AgriLife Extension describes a first draw sample after water has sat in the pipes 6 hours or more, plus a second sample after running the tap at least 5 minutes. Texas A&M AgriLife Extension

Metals panel (copper, chromium, selenium and others)

EPA says heavy metals such as arsenic, copper and lead can come from household plumbing and service lines as well as natural mineral deposits and industry. U.S. EPA

• An older home or old plumbing EPA says heavy metals such as arsenic, copper and lead can come from household plumbing and service lines as well as natural mineral deposits and industry. U.S. EPA
• Central Oklahoma (Garber-Wellington aquifer) The Oklahoma DEQ says arsenic, chromium, selenium and uranium in parts of the Garber Wellington (Central Oklahoma) aquifer sometimes exceed federal drinking water limits. Oklahoma DEQ
• Never had a full test, or 3 or more years since metals were checked The DNR well FAQ recommends bacteria testing every year and heavy metals every three years. Missouri DNR

Uranium and other radioactive elements

EPA's limit for uranium is 30 micrograms per liter; above it the risks are cancer and kidney toxicity. U.S. EPA

• Central Oklahoma (Garber-Wellington aquifer) An earlier OWRB study that included deeper municipal wells found 15 percent of sampled wells over the arsenic limit, 11 percent over the uranium limit, 7.5 percent over selenium and 2 percent over chromium. Oklahoma Water Resources Board
• Never had a full test, or 3 or more years since metals were checked EPA says radioactive elements such as uranium and radium may be naturally present in groundwater in some areas, and drinking them raises cancer risk and can harm the kidneys. U.S. EPA

Radon in water

EPA says 89 percent of that risk is lung cancer from breathing radon released from tap water into indoor air, and 11 percent is stomach cancer from drinking it. U.S. EPA

• Never had a full test, or 3 or more years since metals were checked EPA recommends that private well owners test their drinking water for radon, using a lab the state certification office can point to. U.S. EPA

Fuels, solvents and pesticides (organic chemicals)

EPA says organic chemicals, such as pesticides, solvents and petroleum products, can reach a well through spills, waste disposal and runoff, and can damage the kidneys, liver and nervous system. U.S. EPA

• Near crop fields, feedlots or livestock EPA lists fertilizer storage and use, animal feedlots, manure and pesticide storage and use among the farm sources that can contaminate a private well. U.S. EPA
• Near crop fields, feedlots or livestock EPA says organic chemicals, such as pesticides, solvents and petroleum products, can reach a well through spills, waste disposal and runoff, and can damage the kidneys, liver and nervous system. U.S. EPA
• Floodwater reached the well Texas A&M AgriLife Extension notes that disinfection does not remove fuels, pesticides or heavy metals; suspected chemical contamination needs special testing. Texas A&M AgriLife Extension
• Near a gas station, landfill, oil or gas wells, or a pipeline EPA's checklist of commercial sources includes gas stations, auto repair shops, dry cleaners, junkyards and construction sites. U.S. EPA
• Near a gas station, landfill, oil or gas wells, or a pipeline EPA's checklist of industrial sources starts with oil and gas production and storage, pipelines and refineries, and includes mining. U.S. EPA
• Near a gas station, landfill, oil or gas wells, or a pipeline EPA's checklist also names landfills, abandoned production and disposal wells, and illegal dumping. U.S. EPA

Iron and manganese

Texas A&M AgriLife Extension notes EPA secondary (nuisance, not health) limits of 0.3 mg/L for iron and 0.05 mg/L for manganese; below those levels water should not taste, smell or look bad. Texas A&M AgriLife Extension

• Red, brown or black stains on fixtures or laundry Texas A&M AgriLife Extension says iron leaves reddish brown stains and manganese leaves brownish black stains on laundry, sinks and fixtures, and ordinary detergent does not remove them. Texas A&M AgriLife Extension

Hardness

The U.S. Geological Survey defines water hardness as the amount of dissolved calcium and magnesium in the water. U.S. Geological Survey

• Red, brown or black stains on fixtures or laundry Texas A&M AgriLife Extension recommends a lab test that also measures pH, oxygen, hardness and sulfur, because those decide which treatment will work. Texas A&M AgriLife Extension
• Scale, spots, or soap that will not lather Texas A&M AgriLife Extension says hard water uses up soap, leaves spots and film, and creates scale in water heaters and pipes. Texas A&M AgriLife Extension
• Scale, spots, or soap that will not lather EPA WaterSense advises installing a softener only where hardness is substantial, for example above 180 mg/L or 10 grains per gallon, and choosing one certified to NSF/ANSI 44. U.S. EPA

Sodium

• Someone on a low sodium diet, or you use a softener Texas A&M AgriLife Extension says people on low sodium diets should ask their doctor if sodium is above 20 ppm, which matters because softeners add sodium. Texas A&M AgriLife Extension
• Someone on a low sodium diet, or you use a softener EPA explains that nearly all home softeners use ion exchange, swapping sodium for the calcium and magnesium that cause hardness, and must regenerate periodically. U.S. EPA

Fluoride

Texas A&M AgriLife Extension says fluoride can occur naturally from rock and soil; the primary drinking water standard is 4.0 ppm, and higher levels may cause bone problems. Texas A&M AgriLife Extension

• Never had a full test, or 3 or more years since metals were checked EPA says fluoride occurs in many aquifers; too much can cause skeletal fluorosis, and too much while teeth form can stain or pit them. U.S. EPA