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Environmental Laboratory (NELAP) Accreditation

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

Exit the TCEQLaboratories are assessed against the provisions of the 2009 TNI NELAP standard. After January 31, 2020, they will be assessed against the provisions of the 2016 TNI standard.



- 2016 TNI standard implementation

TNI’s NELAP Accreditation Council has set the formal date for adoption of the 2016 TNI Standard as January 31, 2020.

TNI's press release on the implementation of the 2016 TNI StandardExit the TCEQ

The TCEQ will begin assessing to the 2016 standard on the implementation date.  For laboratories submitting initial applications from April 17 on, it is advisable they use the 2016 standard. 

- Additions to the TCEQ's Fields of Accreditation (FoAs) - MUR and Drinking Water
On April 12, 2019, the TCEQ Laboratory Accreditation Program issued a revision to its Fields of Accreditation (FoAs) to include the following analytical methods:

EPA 608.3, EPA 624.1, and EPA 625.1 in Non-Potable Water; and

SM 4500-Cl¯ B, and ASTM D516-11 in Drinking Water.

The fields were revised to incorporate revised methods from the most recent Method Update Rule (MUR) and add methods requested by the TCEQ Drinking Water Program.  The additional methods and analytes are shown in Appendix A. 

Appendix A (PDF)

The TCEQ Water Quality Division (WQD) will accept analytical data from accredited and in-house laboratories based on the previous Method Update Rule (2012) up to but not beyond August 28, 2019.  The WQD will accept analytical data from non-accredited and in-house laboratories using the new laboratory methods in the current Methods Update Rule (2017) within six months after the FOA effective date or if the laboratory has accreditation for the pollutant and new method in a state other than Texas.  For questions regarding what data will be accepted, please contact the TCEQ WQD at 512-239-4539 or gregg.easley@tceq.texas.gov.  For questions regarding the two new Drinking Water methods, please contact the Quality Assurance Officer for the Water Supply Division at 512-239-4691 or PDWS@tceq.texas.gov.

In order to add any of these additional parameters to an existing scope of accreditation, a laboratory must submit:


  • An amended application
  • Applicable FoA sheets
  • A $250.00 administrative fee
  • Associated documentation including:
    • Standard Operating Procedures
    • Demonstrations of Capability and Method Detection Limit Studies
    • Applicable PT results for all parameters being added (that are also Fields of Proficiency Testing (FoPTs) )



  • An amended application
  • Applicable FoA sheets
  • A $250.00 administrative fee


Note:  The laboratory will not have to pay the $250 administrative fee to change their scope of accreditation if it is done as part of the laboratory’s annual renewal.  Any applicable category fees will still apply.  If a laboratory has submitted PT results for EPA Methods 608, 624, and 625, they are not required to submit PT results for EPA Methods 608.3, 624.1 and 625.1.

TCEQ will review applications in the order they are received.  Laboratories submitting incomplete or inaccurate applications will be notified of the deficiencies and will need to submit a corrected application.  The corrected applications will be placed in the queue based on the date TCEQ receives the corrected application.  Due to the time required to review the applications, any initial or corrected application received after May 28, 2019, may not be reviewed by August 28, 2019.

Link to the EPA Methods Update Rule - 2017 web pageExit the TCEQ


Subscribe to Laboratory Accreditation Program e-mail updates

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

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


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Application, Fields of Accreditation, Checklists, and Procedures

Application (PDF) (Revision 9 - June 2017)

Fields of Accreditation (FoAs) (PDF) (Revision 18 - April 2019)


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)


Accreditation applications in progress (PDF)


For administrative information, please contact our records specialist at 512/239-3754 or e-mail us at labprgms@tceq.texas.gov.


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 labprgms@tceq.texas.gov.


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Laboratory Resources

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

FAQ guides (PDF)


Corrective Action Response (CAR) form.

CAR form (Word)

Corrective Action Response Guidelines For TCEQ Accredited Laboratories (Presentation from 2017 Trade Fair) (Powerpoint)


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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

Link to the EPA Methods Update Rule - 2017 web pageExit 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

Title 30, Texas Administrative Code, Chapter 25Exit the TCEQ , Subchapters A and B (for a schedule of fees refer to §25.30)



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