Tank & Well

How Often Should You Test Your Well Water?

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Starter content. This is an early, abbreviated guide published while our full library is being written. The guidance below is accurate but brief — a fuller version is coming.

If your drinking water comes from a private well, no utility, no town, and no government agency tests it for you. Roughly 23 million U.S. households are their own water company — and the only water that gets checked is water somebody decided to check.

The basic schedule

  • Every year: total coliform bacteria and E. coli, plus nitrates. These are the two headline risks — bacteria indicate that surface contamination is reaching your water, and elevated nitrate is especially dangerous for infants.
  • Every 3 years or so: a broader panel — pH, hardness, iron, manganese, total dissolved solids, and, at least once, arsenic and lead. Local geology decides which of these matter most where you live.

Test sooner if anything changes

Don’t wait for the calendar if the water’s taste, smell, or color changes; after a flood; after well or plumbing repairs; if someone in the household is pregnant or an infant is drinking formula mixed with the water; or if a neighbor’s well turns up contaminated.

How to actually get it tested

You have two good options. Your county health department or state lab often offers free or low-cost bacteria/nitrate tests — call them first. Or use a certified mail-in lab kit: you fill the bottles from your tap, ship them overnight, and get a plain-English report back in about a week. Either way, make sure the lab is state-certified for drinking water.

Frequently asked questions

How often should a private well be tested?

The CDC and EPA recommend testing private well water at least once a year for total coliform bacteria and nitrates, and about every three years for a broader panel including pH, hardness, and metals like iron, manganese, and arsenic.

When should I test my well more often than once a year?

Test right away if the taste, color, or smell changes; after flooding or nearby land disturbance; after any repair to the well or plumbing; if someone in the house is pregnant or you're mixing infant formula; or if neighbors find contamination in their wells.