What to test for
Idaho DEQ and the health districts recommend that every private well be tested for total coliform bacteria and nitrate every year. In the Treasure Valley, add arsenic, uranium, fluoride, iron, manganese, hardness, and total dissolved solids at least once, and again if you notice a change in taste, color or odor, after flooding, or after work on the well. If you are within a Nitrate Priority Area, nitrate every year is not optional. If an infant or a pregnant person drinks the water, test nitrate before they do. EPA: “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.”
Who does the testing
Use an Idaho-certified drinking water laboratory. The health districts, Central District Health (Ada, Boise, Elmore) and Southwest District Health (Canyon, Gem, Payette, Owyhee, Washington), run well water programs and can point you to local labs and sampling bottles. Mail-in kits from a certified lab such as Tap Score cover the full Treasure Valley panel in one order; test strips are useful for screening hardness, iron and nitrate but are not a lab result.
Reading the result
Compare each value with the federal limit shown on our contaminant guides. The guide also shows what nearby public systems and wells have found, so you can see whether your result is typical for the area. Then use the lookup tool or your ZIP well page to see which certified filters address the contaminants that came back high.
Keep the paper
Keep every lab report. A history of results is the most useful thing a well owner can hand a buyer, a plumber, or a health district. If you are willing, upload the report on your ZIP page; we store the values with a location rounded to about 1 km and never the address.