Notes for people on private wells

If your home gets water from a private well, nobody tests it for you. U.S. EPA rules that protect public water systems don't apply to private wells, so testing is up to the owner.^CDC

This site collects the boring but useful details in one place: what to test for, how to read the numbers on a lab report, which rules apply in your state, and who to call locally. We take each fact from a government or university source, link to it, and date the page so you can see when we last checked it.

Start here: guides

• How to read your well water test resultsWhat iron, manganese, hardness, sulfur (H2S), pH, nitrate, coliform/E. coli, and arsenic numbers mean, compared with EPA and state limits, with sources.Last checked 2026-10-21
• Arsenic in well water: the best way to test, and treatment optionsHow to test a private well for arsenic, what the 10 µg/L and 5 µg/L numbers mean, and which treatment types state agencies say work (and don't), with sources.Last checked 2026-10-21
• Iron in well water: what to test, and what to buyHow to figure out what kind of iron problem you have, and which treatment Penn State Extension and Maine CDC match to each iron level, from softeners to greensand to chlorination with filtration. With sources.Last checked 2026-10-21
• Whole-house vs. point-of-use filters for well water: which problems need whichWhen a well problem needs whole-house (point-of-entry) treatment and when a single-tap (point-of-use) unit is enough, based on what state agencies say about each contaminant. With sources.Last checked 2026-10-21
• Best way to test well water: state lab, county health department, certified lab, or mail-in kitThe main ways to get a private well tested, what a full panel should include, how to take a sample so the result means something, and what to do with the report. With sources.Last checked 2026-10-21
• Nitrate in well water: testing, infants, and treatment optionsWhy nitrate matters most for babies, which wells are most at risk, why boiling makes it worse, and the treatment types state agencies list. With sources.Last checked 2026-10-21
• How often to test a private well: CDC and state schedules side by sideYearly, every 3–5 years, or just once. A side-by-side comparison of what CDC and the health and environment agencies in NH, ME, MI, PA, NJ and Union County, NC recommend, plus the events that should prompt a test. With sources.Last checked 2026-10-21
• Uranium and radon in well water: testing and treatmentWhat the uranium, gross alpha and radium standards are, why radon in well water is mostly an air problem, how common radon is in New Hampshire wells, and the treatment types Maine CDC lists. With sources.Last checked 2026-10-21
• Shock chlorinating a well: when it helps, how it's done, and retestingWhen agencies recommend shock chlorination, how often it actually clears bacteria, key safety points from state and county procedures, and the retest schedule. With sources.Last checked 2026-10-21

County pages

Each county page lists the local health department contact, the state's private-well rules, and where to find a certified lab, with sources and a "last checked" date.

See all counties →

How this site works

• Sources first. Every limit, rule, price, and phone number links to the agency or lab that published it. If we can't verify something, we leave it out.
• Dated pages. Rules and prices change. Each page shows when we last checked it.
• No product pitches dressed up as advice. We may add affiliate links later, and if we do, we'll say so on the page. See our affiliate disclosure.