How often should I test my well water, and for what?

Test at least once a year. The CDC and EPA both recommend yearly tests for total coliform bacteria, nitrates, total dissolved solids and pH. Test again right away if the water's taste, color or smell changes, after flooding or nearby ground disturbance, after repairs to the well or pump, or when someone in the home becomes pregnant or a child moves in. In Texas, the Texas Well Owner Network also screens for E. coli and, in some areas, arsenic. Its screenings have found that roughly 15 to 20 percent of samples test positive for coliform bacteria, which is why yearly testing matters even when water looks clean. Ask your local health department about other local contaminants.

Check your local rule. This varies by state, county or city. Your permitting office has the final word; the official lookup pages below show you who that is.

Sources

• Guidelines for Testing Well WaterCenters for Disease Control and Prevention (CDC)
• Protect Your Home's WaterU.S. Environmental Protection Agency (EPA)
• How often should I get my well water tested?Texas Water Resources Institute, Texas A&M AgriLife