Testing Labs

Find a Certified Water Testing Lab

Use a state-certified or NELAP-accredited lab for drinking water and private well testing. Always verify current certification directly with the lab or your state program before submitting samples.

Verify Before Submitting Samples

Lab certifications change. Always confirm that a lab's current certification covers the specific contaminants you need tested before submitting samples. Check with your state's laboratory certification program for the authoritative, up-to-date list.

Authoritative Resource

EPA National Certified Lab Directory

The EPA maintains the definitive national database of certified drinking water testing laboratories organized by state and contaminant type. This is the most comprehensive and current resource — always use it to find certified labs.

Search EPA Certified Lab Database

Testing Guides by Contaminant or Concern

Start with the guide that matches your specific concern — each covers what to test, how, what results mean, and next steps.

Public Utility vs. Private Well: Who Needs to Test?

I'm on a public water utility

  • Your utility is required to test and report results to EPA
  • Check compliance records and the PFAS Watchlist first — it may answer your question without testing
  • If concerned about lead: test at your own tap using a first-draw sample
  • If concerned about PFAS: check PFAS Watchlist records before ordering a test

I have a private well

  • Private wells are not covered by federal EPA utility monitoring rules
  • Testing is your responsibility — no required schedule exists federally
  • Most state programs recommend annual bacteria and nitrate testing at minimum
  • Additional tests depend on your location, local geology, and nearby land use
Well water testing guide →

How to Choose a Water Testing Lab

Match certification to contaminant

Not all labs are certified for all tests. A lab may be NELAP accredited but not specifically certified for PFAS analysis using EPA Method 533 or 537.1. Ask for the specific certification before submitting.

Use state-certified labs for legal purposes

If results will be used for regulatory compliance, real estate transactions, or formal documentation, the lab must be certified by your state program — not just nationally accredited.

Mail-in kits vs. local labs

Many certified labs offer mail-in sampling kits with chain-of-custody forms. These are valid for most purposes. Local labs can provide faster turnaround and in-person guidance on sampling technique.

State Certification Programs

Each state runs its own laboratory certification program. These are the authoritative sources for finding certified labs in your state.

Testing Private Well Water?

Private well testing requirements vary by state. See our state-specific well water guides for testing recommendations and links to each state's certified lab program.

View Well Water Testing Guides →

Before You Test

Check your utility's EPA compliance record first

Before ordering a lab test, review what EPA has already recorded for your utility — violations, PFAS monitoring data, and detected contaminants. This helps you decide which contaminants to prioritize in your test panel.

Testing and Treatment Path

Common Water Testing Questions

Water Testing FAQs