We read 5 results from City of Hollister’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 26,017 people · Water system ID CA3510001 · 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 |
|---|---|---|---|---|
| Lead90th percentile of 31 homes tested, 0 over the action level · listed as a violation in the report · printed as 0.002 ppm · sampled 2023 · Customer taps · 2025 report, page 2 | 2 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal10x the health goal |
| Chlorineaverage · range 0.23 to 2.69 · listed as a violation in the report · Distribution system · 2025 report, page 2 | 1.16 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 31 homes tested, 0 over the action level · listed as a violation in the report · sampled 2023 · Customer taps · 2025 report, page 2 | 0.07 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · listed as a violation in the report · Distribution system · 2025 report, page 2 | 11 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · listed as a violation in the report · Distribution system · 2025 report, page 2 | 54 ppb | None set | 80 ppb | 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.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in City of Hollister’s water between Nov 2023 and Aug 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium29 ppbFound in 13 of 22 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.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
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