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Environmental Laboratory (NELAP) Accreditation

This page offers information on the Agency's National Environmental Laboratory Accreditation Program (NELAP)

Laboratories are assessed against the provisions of the 2009 TNI NELAP standards. 




Effective on December 01, 2014, EPA Method 200.5 was added to the Drinking Water and Non-Potable Water Fields of Accreditation (FoAs). From this date on, laboratories submitting data analyzed by this method need to be accredited or risk having their data refused by the TCEQ. The analytes offered for this method will be:

EPA 200.5 Analytes


Subscribe to NELAC e-mail updates 

Go to this link: Get e-mail updates on your choice of topics.

After entering your e-mail address and personal preferences, mark the Laboratory Accreditation / Environmental Laboratory (NELAC) Accreditation box.


Application, Fields of Accreditation, Checklists, and Procedures


Application (PDF) (Revision 7 - August 2012)

Fields of Accreditation (FoAs) (PDF) (Revision 15 - December 2014)

History of changes to the Fields of Accreditation (PDF)


The current list of accredited laboratories, with links to their scope of accreditation, can be accessed here:

List of Accredited Laboratories (PDF)


The accreditation team uses the 2009 TNI Quality Systems checklist  Exit the TCEQ to determine each laboratory's conformance to the elements of this Standard.  A copy of the TNI checklist is now available directly from their web page.

Be advised that you must have a copy of the TNI Standard ELV1, Management and Technical Requirements for Laboratories Performing Environmental Analyses before you may download this checklist.


TCEQ (Internal) Accreditation Procedures (PDF) (June 08, 2015)


Accreditation applications in progress (PDF)


For administrative information, please contact our records specialist at 512/239-3754 or e-mail us at


For additional information, including suitable ways to obtain traceability of measurements, or to make a complaint, please contact the program manager at 512/239-1990 or e-mail us at


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Frequently Asked Questions (FAQs)

This is a document addressing frequently asked questions regarding the Texas laboratory accreditation program:

FAQ guides (PDF)


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External Links


The NELAC Institute (TNI)  Exit the TCEQ


National Environmental Laboratory Accreditation Program (NELAP) designated proficiency testing providers  Exit the TCEQ


NELAP Fields of Proficiency Testing  Exit the TCEQ


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Our mailing address is:

Texas Laboratory Accreditation Program
Texas Commission on Environmental Quality
P.O. Box 13087, MC-165
Austin, TX 78711-3087


Our physical address for overnight mail delivery is:

Texas Laboratory Accreditation Program
Texas Commission on Environmental Quality
12100 Park 35 Circle, Bldg B, MC-165
Austin, TX 78753



Rules (Including Fees) and Accreditation Standards



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