No government agency monitors the water from a private household well. In Texas, testing it is the owner's job.
How often
The Texas Well Owner Network (TWON), a Texas A&M AgriLife Extension program, recommends testing well water at least once a year. The CDC also recommends testing at least once a year.
What to test for every year
TWON's Water Well Basics lists, at a minimum, nitrate, total dissolved solids (TDS), and E. coli or fecal coliform bacteria. TWON's longer guide lists total coliform bacteria and nitrate annually, plus TDS to watch for trends. The CDC lists total coliforms, pH, TDS and nitrates.
When to test right away
- When you suspect contamination
- When the water's color, taste or odor changes
- After the pump or well has been serviced
- After anyone who drinks the water has a suspicious illness
Near oil and gas activity
TWON's guide suggests that owners near oil or gas development take baseline samples, so that any later changes can be detected. That is relevant to much of the Permian Basin.
Where to send samples
Use a state-accredited drinking water laboratory (see TCEQ's list) or ask your county health department. TWON also holds well screening events around the state.
If testing points to a problem with the well itself (for example a damaged casing or sanitary seal), a well contractor can inspect it. See well rehabilitation.
General information only, not legal or engineering advice. Rules change, so confirm with the agency linked below or a licensed professional before you start work.
Sources
- Texas Well Owner Network (Texas A&M AgriLife): Water Well Basics
- Texas Well Owner Network: Well Owner's Guide to Water Supply
- CDC: Guidelines for Testing Well Water
- TCEQ: accredited (NELAP) laboratories
Last reviewed: October 2026.
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