Questions or Comments:

In-House and On-Site Laboratories

Information for domestic wastewater treatment facilities' laboratory sample testing requirements.


30 Texas Administrative Code (TAC) 25.2Exit the TCEQ
An in-house environmental testing laboratory is a laboratory that provides analytical data to its operator so that the TCEQ can make decisions on:

  • permits or other authorizations issued to the laboratory’s operator;
  • compliance matters and enforcement actions taken concerning the laboratory’s operator; or
  • corrective actions taken by the laboratory’s operator to satisfy statutes, rules, or commission orders.

An on-site environmental testing laboratory is an in-house environmental testing laboratory located at a regulated entity.

Conditions Under Which the Commission May Accept Analytical Data

The commission may accept analytical data provided by a non-accredited environmental testing laboratory for any matter under the commission’s jurisdiction relating to permits or other authorizations, compliance matters, enforcement actions, or corrective actions. The laboratory must be an on-site or in-house environmental testing laboratory that is inspected at least every three years by the Executive Director.

Inspections by the Executive Director

Inspections are performed every three years by TCEQ regional staff during comprehensive compliance investigations in most cases. The investigator will typically use a water quality in-house laboratory compliance investigation checklist. Questions on the checklist include, but may not be limited to:

  • Does the exempt in-house laboratory perform analyses only for its own reporting to the TCEQ?
  • What was the condition of the laboratory at the time of the investigation?
  • Does the laboratory utilize approved methods? 30 TAC 319.11Exit the TCEQ
  • Do observations and laboratory records indicate compliance with proper sampling and analysis protocols? 30 TAC 319.11Exit the TCEQ
  • Were there any concerns noted regarding analytical parameters evaluated at the time of the investigation? 30 TAC 319.11Exit the TCEQ
  • Were there any concerns noted regarding the laboratory’s Quality Assurance program? 30 TAC 319.6Exit the TCEQ and Table 3 in 30 TAC 319.9(c)Exit the TCEQ (Self-Monitoring and Quality Assurance Schedules)

Operator Training

Laboratory training is recommended for operators that do not have training or experience. To obtain a list of approved classroom training providers, contact the Wastewater Licensing staff at (512) 239-6133. You can also contact your local Small Business and Local Government Assistance (SBLGA) compliance specialist for assistance finding training. 

Where can I find more information and assistance?

The TCEQ's Small Business and Local Government Assistance Section offers free, confidential help to small businesses and local governments working to comply with state environmental regulations. Call us at (800) 447-2827 or visit our Web page at