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Environmental Laboratory (NELAP) Accreditation

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



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


Effective on July 1, 2013The NELAC Institute (TNI) updated their Fields of Proficiency Testing (FoPTs) for the Non-Potable Water matrix:

Laboratories that currently have primary accreditation for any of the new analytes in the Non-Potable Water FoPTs have one year to complete two successful PT analyses and to include the new analytes into their regular semi-annual PT rotation. Labs that do not meet the PT requirements in the TNI standard for continued accreditation (2009 TNI V1M1 para 4.2.1) for these parameters after July 01, 2014 risk losing those accreditations. 

Any laboratories submitting an initial accreditation application or requesting we add any of the the new parameters to a current NELAC scope of accreditation now need to meet the requirements in the TNI standard for initial accreditation (2009 TNI V1M1 para 4.1) for the new analytes.

For those analytes that were dropped from the Non-Potable Water Fields of Proficiency Testing (FoPTs), PTs are no longer required for initial or continued accreditation (2009 TNI V1M1 para 1.3.2).


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)


Laboratories are assessed against the provisions of the 2009 TNI NELAP Standards. (PDF) Exit the TCEQ


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) (October 24, 2012)


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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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


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Rules (Including Fees) and Accreditation Standards


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