Texas well water testing: AgriLife guidance, TWON screenings and accredited labs
Short answer: Texas A&M AgriLife Extension says to test well water at least once a year for nitrate, total dissolved solids and E. coli or fecal coliform bacteria. Its Texas Well Owner Network runs low-cost screening events, typically $15 per sample, and TCEQ lets you search for accredited labs.
The U.S. Geological Survey estimated that about 1.32 million people in Texas supplied their own household water in 2015. USGS says the most common source of self-supplied water is a well. [source] [source]
What to test every year
Texas A&M AgriLife Extension says Texas landowners are responsible for the drinking water from their private wells. At a minimum, have the water tested every year for nitrate, total dissolved solids, and E. coli or fecal coliform. It also notes that arsenic and radionuclides can occur naturally in wells. [source]
Low-cost screenings: Texas Well Owner Network
The Texas Well Owner Network (TWON), run by AgriLife Extension and the Texas Water Resources Institute, holds well water screening events around the state. [source] At a typical event, such as Roby's in October 2026, samples were screened for total coliform, E. coli, nitrate-nitrogen and salinity for $15 per sample. Participants were asked to attend a follow-up meeting to get their results. [source] Check TWON for upcoming events in your area.
Accredited labs
For a fuller analysis, search for an accredited lab on TCEQ's NELAP laboratory accreditation page. [source]
County guides
No county pages for this state yet. Your local health department is the first stop, per EPA guidance. [source]
FAQ
How often should Texas well owners test their water?
Texas A&M AgriLife Extension says to test well water at least once a year for nitrate, total dissolved solids and E. coli or fecal coliform bacteria. Its Texas Well Owner Network runs low-cost screening events, typically $15 per sample, and TCEQ lets you search for accredited labs.
What is a TWON well screening?
The Texas Well Owner Network holds events where well owners drop off samples that are screened for coliform, E. coli, nitrate-nitrogen and salinity, then attend a meeting to get results. The October 2026 Roby event cost $15 per sample.
Sources
- USGS – Estimated Use of Water in the United States, County-Level Data for 2015 (domestic self-supplied population) (accessed 2026-10-23)
- USGS – Domestic Water Use (accessed 2026-10-23)
- Texas A&M AgriLife Extension (TWON) – Water Well Basics (accessed 2026-10-23)
- Texas Well Owner Network (TWON) (accessed 2026-10-23)
- Texas Water Resources Institute – Private water well screenings set for Roby area, Oct. 13, 15 (2026) (accessed 2026-10-23)
- TCEQ – Environmental Laboratory (NELAP) Accreditation (accessed 2026-10-23)
- US EPA – Protect Your Home's Water (accessed 2026-10-23)
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