Test a private well for bacteria and nitrate every year

First find out whether the property has public water or a private domestic well. Private wells generally are not watched like public water systems. The owner should use a state-accredited lab each year. Ask the lab to test for total coliform bacteria and nitrate.

Test again after a flood, a well repair, or a nearby contamination event. Do the same if the water’s taste, smell, or color changes. Ask the county environmental health office whether to test for anything else. A home test kit does not replace a certified lab result.

Do not consume the water if a result is over a primary drinking-water standard. Wait until the problem has been checked and fixed. Ask county environmental health about safe water, a test to confirm the result, treatment, or well repair. Do not guess that boiling or a home filter will solve the problem.

A newer rule has a narrow reach. It applies only to rental-property wells within a free testing program. A State or Regional Water Board must fund or regulate that program. In those areas, the owner must use the program and share results with tenants within 10 days. After a result exceeds a standard, the owner must provide safe water only if the program offers it and the eligibility rules are met. Residents cannot be charged for the test or replacement water.