How to Test Your Well Water: A Step-by-Step Guide
1. Pick a certified lab
EPA advises using a lab certified for drinking water by your state. Certification is per test, so confirm the lab is certified for each test you want and that it accepts private well samples. Start from your state page.
2. Decide what to test
EPA's yearly baseline is total coliform bacteria, nitrate, total dissolved solids and pH. Add tests for local problems such as arsenic, manganese, uranium, lead or PFAS. Our which test do I need? quiz builds a list for you.
3. Use the lab's bottles
- Bacteria bottles are sterile and often contain a tablet to neutralize chlorine. Don't rinse them or touch the inside.
- Take the sample from a cold tap that doesn't swivel, with the aerator removed, after running the water as the lab tells you.
- Some tests (like lead) need a 'first draw' sample from water that sat overnight. Read the instructions for each bottle.
4. Get it to the lab on time
Bacteria samples must be kept cold and usually reach the lab within about a day, so many labs accept them only early in the week. Chemistry samples are less time-sensitive. Ask the lab about drop-off hours or shipping.
5. Read the report
Compare each result with the limit printed on the report, and check the units (mg/L is ppm; µg/L is ppb). Our results reader compares numbers with EPA and Health Canada limits.
Sources
- EPA: Protect your home's water
- EPA: State drinking water lab certification programs
- Penn State Extension: Water tests, what do the numbers mean?
- Penn State Extension: Coliform bacteria
Questions
Can I use a home test kit instead of a lab?
Home kits can give a rough idea, but EPA advises using a state-certified lab, and many lenders and health departments accept only certified lab results.
How long do results take?
Bacteria results often come back within a few days. Other tests can take one to several weeks. Ask the lab.
Free well water safety checklist
15 family-friendly steps based on CDC and EPA guidance. Print it, keep it on the fridge, and know when to call a certified lab.
More guides
- Flood Protection for Well Owners: Before, During and After a FloodRaise and seal the wellhead, know your pump shutoff, then disinfect and test with a certified lab after any flood.
- PFAS “Forever Chemicals” in Private Wells: Why You Should TestFederal PFAS rules protect public water systems — not private wells. Here’s what “forever chemicals” mean for well owners and how to get tested.
- Nitrates in Well Water and Blue Baby Syndrome: Who Must TestNitrate in well water can cause blue baby syndrome in infants. Learn who is at risk, when to test, and how to find a certified lab.
- Arsenic in Private Well Water: The Invisible Risk UndergroundArsenic in groundwater is often naturally occurring and invisible. USGS research shows millions of private-well users may be above the EPA drinking-water standard.