Well water testing labs in Texas

Last verified October 26, 2026 against the official state list (Updated 03/26/2026).

The Texas Commission on Environmental Quality (TCEQ) publishes a table of NELAP-accredited labs that analyze drinking water for total coliform bacteria and E. coli, lead and copper, and water quality parameters. TCEQ's private well sampling guide tells well owners to find a lab on its accredited list. We copied the table below, grouped by county, so you can find a lab near you.

Labs by county

Angelina Bastrop Bexar Bowie Brazoria Brazos Cameron Collin Comanche Dallas Denton Ector El Paso Erath Fort Bend Grayson Gregg Guadalupe Harris Hays Hidalgo Hill Hutchinson Kerr Llano Lubbock McLennan Midland Montgomery Nacogdoches Nolan Nueces Orange Polk Randall San Jacinto Smith Tarrant Taylor Tom Green Travis Victoria Walker Webb Wichita Williamson

Angelina County

Bastrop County

Bexar County

Bowie County

Brazoria County

Brazos County

Cameron County

Collin County

Comanche County

Dallas County

Denton County

Ector County

El Paso County

Erath County

Fort Bend County

Grayson County

Gregg County

Guadalupe County

Harris County

Hays County

Hidalgo County

Hill County

Hutchinson County

Kerr County

Llano County

Lubbock County

McLennan County

Midland County

Montgomery County

Nacogdoches County

Nolan County

Nueces County

Orange County

Polk County

Randall County

San Jacinto County

Smith County

Tarrant County

Taylor County

Tom Green County

Travis County

Victoria County

Walker County

Webb County

Wichita County

Williamson County

Notes on this list

• TCEQ's table covers labs that analyze drinking water samples for public water systems. Many also take samples from private well owners, but call first to confirm they accept private samples, plus drop-off hours and prices, as TCEQ advises.
• For bacteria testing, timing matters. On the TCEQ table, 21 of the 76 microbial labs say they accept microbial samples on Saturdays; others accept weekend samples only in emergencies or not at all. Ask the lab before you sample.
• County is shown as printed on the TCEQ table.
• For other contaminants (arsenic, nitrate, fluoride and more), TCEQ's accredited laboratory database lets you search by matrix and analyte.

What the state recommends

• TCEQ says testing for total coliform and E. coli by an accredited lab is the first step to finding out whether your well is contaminated, for example after flooding, a loss of water pressure, or recurring digestive problems. Ask the lab for a sterile container and sampling form; results usually take two to three days. Source
• If total coliform is found, TCEQ says not to use the water for drinking, bathing, cooking or washing dishes. Boil or disinfect it, or use bottled water, disinfect the well, and retest until the lab reports total coliform absent. Source

State contacts

• TCEQ (help finding a drinking water lab): 512-239-3754 Source

Sources

• TCEQ: Public Water System Lab Map Table (PDF, updated 03/26/2026)
• TCEQ: Public Water System Lab Map Table (Excel)
• TCEQ: Accredited Drinking Water Laboratories in Texas (map)
• TCEQ GI-433: How to Sample Your Private Well Water for Microbial Contaminants
• TCEQ: List of Accredited Laboratories (NELAP database)

Other states

Well water testing labs in Minnesota · Well water testing labs in Vermont

Also read: well water danger guides on PFAS, nitrates, arsenic, lead, and bacteria.