Well Water Test Kit Guide: What to Test For, and How to Read Results

What should a well water test kit test for?

The EPA's guidance for private wells is a yearly test for total coliform bacteria, nitrate, total dissolved solids, and pH. That is the baseline because those four catch the problems you cannot taste: bacteria from surface water reaching the well, nitrate from septic or fertilizer, and water chemistry that corrodes pipes. Add iron, manganese, and hardness if you have staining or a metallic taste, and ask your state health department which regional tests apply where you live; arsenic, radon, uranium, and fluoride vary by geology, and lead depends on your own plumbing rather than the well.

Home kit or certified lab?

Home kits are screening tools. Test strips read hardness, pH, iron, nitrate, and chlorine well enough to tell you which direction to look. A presence-absence bottle tells you whether coliform bacteria are there at all. Neither replaces a certified laboratory when the result has consequences: a home sale, a lender, an infant in the house, or an illness. Every state publishes a list of certified drinking water labs, most county health departments run low-cost coliform and nitrate testing for private wells, and mail-in labs cover the rest. Our own well water test kit is coming this winter and will end in a diagnosis rather than a color chart.

How to read the results

Coliform present means something is reaching the well from the surface: find the entry point, shock the system, and retest, following the coliform guide. E. coli present means stop drinking the water until that retest is clean. Nitrate above the EPA limit of 10 milligrams per liter, measured as nitrogen, is a real health limit, most serious for infants, and shocking the well does nothing for it; the source is the aquifer and the fix is a treatment system or a different water source for the baby. Iron above 0.3 milligrams per liter and manganese above 0.05 are the EPA's secondary standards, which is the point where staining and taste begin, and they are aesthetic rather than health limits. A pH outside 6.5 to 8.5 is water that either corrodes or scales your plumbing. Hardness is a soap and scale question, not a safety one.

Where to get well water tested near you

Start with your county health department, which often tests coliform and nitrate for private wells at cost, then your state's list of certified drinking water laboratories, then the county extension office, which in many states runs seasonal well testing clinics. In Wisconsin, the State Laboratory of Hygiene tests bacteria for $35 and nitrate for $35, ships the bottles free, and takes orders at 800-442-4618; county programs such as Rock and Vernon run the bacteria test for about $30. Whichever you use, ask for total coliform and E. coli plus nitrate at minimum, take the sample exactly the way the lab instructs, and get it there within the hours the lab specifies. Keep every result: a well with a history is a well you can reason about, and the record of the well itself is on your state's page.