Well Water Test Kits.

Private wells fall outside EPA oversight. Your municipal water provider tests its system continuously and treats it before delivery. Your well is your system — there is no one else monitoring it, treating it, or responsible for its safety. What you put on the land around it, what your neighbors do with theirs, and what happens geologically beneath it all affect your water quality over time.

The EPA and CDC recommend testing private wells at minimum annually for four parameters: total coliform bacteria, nitrates, total dissolved solids (TDS), and pH. These are not exhaustive, but they cover the contamination categories most likely to affect health. Bacteria and nitrates are the health-critical priorities — both can cause serious illness without any visible change to the water's appearance, taste, or smell.

Depending on where you live and what activities occur nearby, additional testing may be warranted: arsenic (common in certain geological formations in the Northeast and West), radon, volatile organic compounds (VOCs) if near industrial sites or former agricultural land, or manganese. Your state health department can tell you what contaminants are commonly found in groundwater in your county — call them before you buy a kit.

Many state and local health departments offer free or low-cost well water testing for bacteria and nitrates. This is the first call to make, not the last.

Field test kits for well water use growth media and colorimetric reagents that expire, typically within 1 to 2 years. Keep 2 to 3 kits on hand — one for annual screening, one or two in reserve for post-flooding or post-repair checks. Rotate on the same schedule as other emergency consumables.

Mail-in lab kits typically have a longer collection bottle shelf life. Follow the specific kit's instructions for collection, handling, and shipment timing. Most require the sample to reach the lab within 24 to 48 hours of collection and must be kept cool (not frozen) in transit.

A positive bacteria result: stop drinking the water. Use bottled water for drinking and cooking until the well is treated and retested. Contact your local health department. Shock-chlorinate the well per your state's guidance, wait 24 to 48 hours, then retest with a certified lab. Do not return to the well until two consecutive negative results confirm the contamination is cleared.

Elevated nitrates: a particular risk for infants under 6 months, pregnant women, and immunocompromised individuals. Use bottled water or a filter certified for nitrate removal for these household members until the source is identified and addressed. Boiling does not reduce nitrate and can concentrate it.

After flooding: do not assume the well is safe because it looks and smells normal. Flood-affected wells should be shock-chlorinated and tested by a certified lab before returning to use. Field kit results after flooding are not sufficient — the contamination may be at levels below the kit's threshold.

Per EPA private well guidance (EPA: Protect Your Home's Water) and CDC (CDC: Well Water Testing Guidelines). Verified June 2026.