How do I know if a lab is certified?

Check with your state drinking water or environmental agency, which maintains a list of certified laboratories. You can also ask the lab directly which contaminants it is certified to analyze.

Testing & Safety

How to Choose a Certified Water Testing Lab

Health-based water decisions depend on a state-certified laboratory. This guide shows how to find and work with one for trustworthy results.

By Know Your Well Water Editorial TeamReviewed October 29, 20262 min read

Quick Answer

For any health-based result, use a laboratory certified by your state to test drinking water. Certified labs follow approved methods and quality controls, so their results are reliable enough to act on. Your state or county health department can provide a list of certified labs.

Why certification matters

A state-certified lab is audited to use approved analytical methods and maintain quality controls. That is what makes a result trustworthy enough to base health decisions on. Uncertified labs or consumer gadgets may be fine for curiosity, but not for confirming safety.

How to find and use a certified lab

1Ask your state or county health department for a list of state-certified drinking water laboratories.
2Confirm the lab is certified for the specific contaminants you need, such as bacteria, nitrate, arsenic, or PFAS.
3Request their sample kit and collection instructions before you start.
4Follow the instructions exactly, including bottle type, timing, and keeping samples cold.
5Deliver samples within the stated holding time and keep your certified report.

Match the lab to the test

Some tests, like PFAS and radiological contaminants, require specialized accreditation. Confirm the lab can run exactly what you need before sending a sample.

Private wells are your responsibility

Because private wells are generally not federally regulated, no agency tests your water for you. Choosing a good lab is part of protecting your own household.

Frequently asked questions

How do I know if a lab is certified?: Check with your state drinking water or environmental agency, which maintains a list of certified laboratories. You can also ask the lab directly which contaminants it is certified to analyze.

Sources & references

Well Testing — CDC, accessed October 29, 2026
Protect Your Home’s Water: Private Wells — US EPA, accessed October 29, 2026

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