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How to Test Your Well Water: A Practical Guide

Because private wells are usually not regulated like public systems, testing is the owner’s job. Here’s what to test for, how often, and how to do it right.

By Know Your Well Water Editorial TeamReviewed October 26, 20264 min read

Quick Answer

Test a private well at least once a year for total coliform bacteria and nitrate, plus pH and anything of local concern, using a state-certified laboratory. Test more often — and more broadly — after flooding, repairs, a change in taste/odor/appearance, a new baby in the home, or when buying a property. Home screening kits are useful for monitoring, but base health decisions on certified-lab results.

What to test for

There is no single universal panel, but CDC and EPA guidance points to a core set for most private wells, plus extras based on your region and situation.

PriorityTypical testsWhy
Every yearTotal coliform bacteria, nitrate, pHCore safety and corrosivity indicators
Based on areaArsenic, lead, fluoride, manganese, uranium, radonNaturally occurring or local contaminants where documented
SituationalPesticides/VOCs, PFAS, hardness, iron, sulfateNearby land use, taste/odor/staining, or treatment planning
A practical starting framework (confirm local recommendations)

How often to test

  • At least annually for bacteria and nitrate (CDC recommendation).
  • After any flooding, well work, or new nearby activity.
  • When you notice a change in taste, smell, color, or clarity.
  • Before a vulnerable person (infant, pregnant, immunocompromised) relies on the water.
  • At real-estate transactions, when a current test is often requested.

Where to get a reliable test

Use a certified laboratory

  1. 1Contact your state or local health department for a list of state-certified drinking water laboratories.
  2. 2Ask the lab which bottles and preservatives to use and how to collect the sample — correct collection matters as much as the analysis.
  3. 3Follow the hold-time and shipping instructions exactly (bacteria samples are especially time-sensitive).
  4. 4Keep your results; they become a baseline you can compare future tests against.

Home kits vs. certified labs

Home test strips and kits are convenient for ongoing screening (for example, checking hardness or a quick nitrate indication). For health-based decisions — bacteria, arsenic, lead, nitrate — rely on a certified laboratory, and confirm any borderline screening result with one.

Appearance is not safety

Clear, good-tasting water can still contain bacteria, arsenic, nitrate, or lead — none of which you can see, taste, or smell. Only testing can establish whether your water is safe.

After you get results

Compare each result to the appropriate reference value and note whether it is health-based or aesthetic. A positive bacteria result or a health-based exceedance warrants prompt action and a call to your health department; aesthetic exceedances are about comfort and equipment, not immediate safety.

Frequently asked questions

How much does a well water test cost?
It varies widely by lab and panel — a basic bacteria-and-nitrate test is relatively inexpensive, while broad panels covering metals, radionuclides, or PFAS cost more. Ask certified labs in your state for current pricing; we don’t publish invented figures.
Can I use tap water appearance to decide if I need a test?
No. Many serious contaminants are invisible and odorless. Follow a testing schedule regardless of how the water looks, and test immediately after any change or event.

Sources & references

This guide is documentary research and general information, not a laboratory analysis or professional assessment of your specific well. See our disclaimer.