Skip to content
TapBuff
ZIP

Is San Marcos, TX tap water safe?

6 utilities serve San Marcos, by EPA’s records. Here is what EPA’s and Texas’s records show for each, against the legal limits and the stricter health goals.

Matched to your utility using EPA records.

The short answer

3 of the 6 utilities serving San Marcos have a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Texas’s records: City of San Marcos, Crystal Clear SUD and Maxwell SUD.

City of San Marcos, which serves the most people here, has 1 result above the legal limit and 1 result above the health goal. The worst: Total trihalomethanes (TTHM) at 53.4 ppb, above the legal limit.

A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in San Marcos’s ZIP codes, from EPA’s estimates.

What handles it

Each of these is certified, on a certifier’s listing, for a result above a line in City of San Marcos’s water, which serves the most people here. Another utility’s report names what handles its own results.

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Every claim, and more filters, in the full report

Water testing near San Marcos

A utility tests the water it sends out. A test of your own tap shows what your pipes add, and on a private well it is the only test there is. It takes a lab Texas certifies.

The 3 labs Texas certifies closest to San Marcos, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Edwards Aquifer Research & Data Center, Texas State University

    San Marcos, TX · about 5 miles

    Certified for bacteria

    (512) 245-2329

  • Aqua-Tech Laboratories, Inc.

    Austin, TX · about 22 miles

    Certified for bacteria, lead and copper

    (512) 301-9559

  • Texas Department of State Health Services Laboratory Services Section

    Austin, TX · about 31 miles

    Certified for bacteria, lead and copper

    (512) 458-7318

Texas Well Owner Network, Texas A&M AgriLife Extension: Well Informed screening events, where well owners bring in water samples to be screened for common contaminants, followed by an hour-long session explaining the results. Upcoming events are on the network's calendar. Trainings, Texas Well Owner Network.

All 80 certified labs for Texas

ZIP codes in San Marcos

Which ZIP codes are in San Marcos: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: TCEQ, drinking water laboratories approved for public water system samples; distances from the Census 2020 ZIP code tabulation area gazetteer.

Near San Marcos

Towns nearby with a page of their own.

What to do next