Choosing an analytical laboratory

Check accreditation status

Accreditation assures that a lab can conduct analyses according to prescribed methods. While it is not proof of the quality of all of their data, it means that the lab is capable of providing accurate, comparable, complete, and defensible data. If you need a lab to use a specific analytical method, confirm that the lab is accredited for the specific method you need.

We maintain several ways to make it easier to find an environmental or drinking water laboratory that is accredited for the analyses you need. See the links below to locate a lab in your area:

• Use our Lab Search database to find labs that are accredited for a specific analytical method or to list the specific analytical methods for any accredited lab.
• Use the interactive lap map to find labs.
• Use our printable lists of accredited labs.
  • All accredited labs by name
  • Drinking water labs by county
  • Drinking water labs with all analyses

If you have trouble finding an accredited lab, contact us.

See quality control tests

Expect the lab to report the results of quality-control tests, such as blank, standard, and duplicate samples, at no extra cost. Check both precision and bias estimates to judge whether the lab has done accurate work. Ask for results of quality-control tests done with the batch in which your samples were analyzed.

If there are any questions concerning interpretation of the control results, contact us.

Labs must meet holding-time requirements

Labs must be able to meet holding-time requirements for samples. Most labs provide a form to record the time a sample was taken and by whom. When the sample is delivered to the lab, the person receiving the sample should sign your form and return a copy showing the date and time the sample was received by the lab. The lab’s report back to you should show when the sample was extracted, if an organic analysis is being done, and when it was analyzed. This establishes that holding times were met and is essential in case the data is legally challenged.

Confirm that they manage their dangerous waste properly

Laboratories must properly manage dangerous waste. Ask the lab to certify that it will dispose of the samples according to existing regulations or return the samples to you for proper disposal.