We read 11 results from Texas State University - San Marcos’s 2025 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 43,552 people · Water system ID TX1050003 · Read the district’s 2025 report (opens in a new tab)
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Results from the 2025 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Copper90th percentile of homes tested, 1 over the action level · listed as a violation in the report · sampled 2023 · Customer taps · 2025 report, page 5 | 1.06 ppm | 0.3 ppm | 1.3 ppm (action level) | Above the health goal3.5x the health goal |
| Gross alpha (radioactivity)highest measured · range ND to 4 · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 5 | 4 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of homes tested, 0 over the action level · listed as a violation in the report · printed as 0.0013 ppm · sampled 2023 · Customer taps · 2025 report, page 5 | 1.3 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal6.5x the health goal |
| Bariumsingle sample · listed as a violation in the report · Wells · 2025 report, page 5 | 0.04 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorineaverage · range 0.6 to 1.5 · Distribution system · 2025 report, page 5 | 0.95 ppm | None set | 4 ppm | Below the legal limit |
| Disinfection byproducts (HAA5)highest measured · range ND to 2.4 · listed as a violation in the report · sampled 2024 · Distribution system · 2025 report, page 5 | 2.4 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest measured · range 2.5 to 15.3 · listed as a violation in the report · sampled 2024 · Distribution system · 2025 report, page 5 | 15.3 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridesingle sample · listed as a violation in the report · sampled 2023 · Wells · 2025 report, page 5 | 0.19 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)single sample · listed as a violation in the report · Wells · 2025 report, page 5 | 1.96 ppm | 10 ppm | 10 ppm | Below the health goal |
| Total dissolved solidsaverage · range 336 to 432 · Wells · 2025 report, page 6 | 384 ppm | — | 500 ppm guideline | Within the guideline |
| Sodiumaverage · range 18 to 23 · Wells · 2025 report, page 6 | 20.5 ppm | None set | None | No health limit |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Texas State University - San Marcos’s water between Oct 2024 and Apr 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium9.5 ppbFound in 1 of 2 samples · highest resultBelow EPA’s health reference level of 10 ppb
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
Lead
Found: Copper, Lead
What removes it: Reverse osmosis or Certified carbon block or RO.
Radium and uranium
Found: Gross alpha (radioactivity)
What removes it: Reverse osmosis.
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