We read 13 results from Harlingen Water Works System’s 2025 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 85,900 people · Water system ID TX0310002 · 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 |
|---|---|---|---|---|
| Arsenichighest measured · range 3.2 to 3.9 · listed as a violation in the report · Treatment plants · 2025 report, page 5 | 3.9 ppb | 0.004 ppb | 10 ppb | Above the health goal975x the health goal |
| Gross beta (radioactivity)highest measured · range 6.7 to 7.6 · listed as a violation in the report · sampled 2023 · Treatment plants · 2025 report, page 5 | 7.6 pCi/L | 0 pCi/L | 50 pCi/L | Above the health goalThe health goal is zero |
| Uraniumhighest measured · range 3 to 3.2 · listed as a violation in the report · sampled 2023 · Treatment plants · 2025 report, page 5 | 3.2 ppb | 0.6 ppb | 30 ppb | Above the health goal5.3x the health goal |
| Bariumhighest measured · range 0.1 to 0.11 · listed as a violation in the report · Treatment plants · 2025 report, page 5 | 0.11 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloramineaverage · range 0.9 to 5 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 3.7 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · listed as a violation in the report · sampled 2024 · Customer taps · 2025 report, page 4 | 0.02 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 6.9 to 20.8 · listed as a violation in the report · Distribution system · 2025 report, page 5 | 18.9 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 19.5 to 50.8 · listed as a violation in the report · Distribution system · 2025 report, page 5 | 45.5 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.51 to 0.57 · listed as a violation in the report · Treatment plants · 2025 report, page 5 | 0.57 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range ND to 0.53 · listed as a violation in the report · Treatment plants · 2025 report, page 5 | 0.53 ppm | 10 ppm | 10 ppm | Below the health goal |
| Nitrite (as N)highest measured · range 0.05 to 0.05 · listed as a violation in the report · sampled 2022 · Treatment plants · 2025 report, page 5 | 0.05 ppm | 1 ppm | 1 ppm | Below the health goal |
| Seleniumhighest measured · range 3.4 to 5.2 · listed as a violation in the report · Treatment plants · 2025 report, page 5 | 5.2 ppb | 30 ppb | 50 ppb | Below the health goal |
| Turbidity (cloudiness)highest measured · listed as a violation in the report · Treatment plants · 2025 report, page 4 | 0.28 NTU | None set | 1 NTU | Below the legal 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. 1 number we weren’t sure about is held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Harlingen Water Works System’s water between Aug 2023 and May 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium46.9 ppbFound in 8 of 8 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
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.
Radium and uranium
Found: Gross beta (radioactivity), Uranium
What removes it: Reverse osmosis.
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