How often to test your well water
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.
How often
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.
EPA also says to test immediately when you notice a change in the water, such as its odor, color or taste.
EPA suggests testing more often if small children or elderly adults live in the home, or if someone is pregnant or nursing.
The Missouri Department of Health and Senior Services recommends testing at least once a year and any time the well is serviced or the water changes.
Texas A&M AgriLife Extension advises testing every year at minimum for nitrate, total dissolved solids, and E. coli or fecal coliform bacteria.
The Tennessee Department of Environment and Conservation strongly recommends testing private water supplies for bacteria every year.
EPA says to use only laboratories certified for drinking water testing, and notes your local health department may offer private well testing, sometimes free.
Sources: EPA: test every year; Missouri: yearly and after service; Texas A&M: minimum yearly test list; Tennessee: test yearly for bacteria
Whose job it is
EPA says private well owners are responsible for the safety of their own drinking water.
EPA states that private well water is not regulated by the federal Safe Drinking Water Act, nor by most state laws.
USGS says homeowners are responsible for maintaining their well systems and for monitoring water quality.
USGS reports that more than 43 million people, about 15 percent of the U.S. population, rely on private wells.
Missouri requires a water sample only when a private well is installed. After that, the state does not monitor or regulate the water quality.
The Arkansas Department of Health says well water safety is each person's responsibility. Its lab tests private samples for total coliform and E. coli only.
Tennessee has no state requirement to sample private wells. If a lender requires a test, ask the lender which items must be tested.
Sources: EPA: owners are responsible; USGS: homeowners monitor quality; Missouri: water not monitored; Arkansas: each owner is responsible; Tennessee: no state sampling rules
Common questions
How often should I test my well water?
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.