How to Test a Private Well (and How Often)

More than 15 million households in the United States rely on private wells for their drinking water. Because private wells are not regulated under the federal Safe Drinking Water Act, the EPA does not monitor them. This places the burden of ensuring water safety squarely on the homeowner.

When and How Often to Test

The Centers for Disease Control and Prevention (CDC) and the EPA recommend that private well owners test their water at least once every year.

• Annual minimum testing: Total coliform bacteria, nitrates, total dissolved solids (TDS), and pH levels.
• Every three years: Test for radionuclides (like radon or uranium) depending on your local geology.
• Event-driven testing: Test immediately if you replace a well pump, if flooding occurs near the wellhead, if there is known agricultural runoff, or if you notice a change in water taste, odor, or appearance.

Why DIY Test Strips Fall Short

Hardware stores sell cheap water testing kits, usually a strip you dip in a cup. These strips are fine for checking water hardness or basic pH, but they cannot reliably detect dangerous contaminants like E. coli, low levels of lead, or PFAS. For actionable health data, water samples must be analyzed by a state-certified laboratory (ELAP or NELAP accredited) using specific scientific protocols.

Testing for 'Forever Chemicals' and Heavy Metals

While the annual coliform/nitrate test is essential, many homeowners also test for heavy metals (lead, arsenic) and PFAS. Lead typically comes from older home plumbing rather than the well itself, requiring a specific first-draw test. PFAS testing requires extreme care during sample collection (even waterproof clothing or cosmetics can contaminate the sample) and must be analyzed using EPA Methods 533 or 537.1.