We read 12 results from City of San Bruno’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 41,327 people · Water system ID CA4110023 · Read the district’s 2025 report (opens in a new tab)
Open this district in the water lookupCompare with your own test results, see the district map and get matched filters.
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 |
|---|---|---|---|---|
| Bromatehighest running annual average · range 1.9 to 4.1 · Treated water · 2025 report, page 5 | 3.5 ppb | 0.1 ppb | 10 ppb | Above the health goal35x the health goal |
| Chloraminehighest running annual average · range 2.82 to 3.27 · Distribution system · 2025 report, page 5 | 3.09 ppm | None set | 4 ppm | Below the legal limit |
| Chlorideaverage · range ND to 19 · Treated water · 2025 report, page 5 | 9.8 ppm | — | 250 ppm guideline | Within the guideline |
| Copper90th percentile of 39 homes tested, 0 over the action level · printed as 65 ppb · Customer taps · 2025 report, page 5 | 0.07 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 7.8 to 43.8 · Distribution system · 2025 report, page 5 | 24.2 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 12.2 to 54.4 · Distribution system · 2025 report, page 5 | 34.1 ppb | None set | 80 ppb | Below the legal limit |
| Lead90th percentile of 39 homes tested, 0 over the action level · Customer taps · 2025 report, page 5 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Sulfateaverage · range 1 to 45 · Treated water · 2025 report, page 5 | 21 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 24 to 197 · Treated water · 2025 report, page 5 | 117 ppm | — | 500 ppm guideline | Within the guideline |
| Hardnessaverage · range 0.47 to 6.55 · Treated water · 2025 report, page 6 | 3.63 gpg (62 ppm) | — | — | Moderately hard |
| Lithiumaverage · range 24 to 40 · Treated water · 2025 report, page 6 | 30 ppb | None set | None | No health limit |
| Sodiumaverage · range 3.1 to 29 · Treated water · 2025 report, page 6 | 18 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 City of San Bruno’s water between Oct 2024 and Jul 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium40 ppbFound in 8 of 12 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.
More districts: California water quality · All states · Something look wrong? Tell us