We read 19 results from Cal/Am Water Company - San Marino’s 2025 water quality report. No results over a legal limit; 4 above a health goal or guideline.
Serves about 47,995 people · Water system ID CA1910139 · 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 |
|---|---|---|---|---|
| Arsenicaverage · range ND to 2.8 · San Marino wells · 2025 report, page 6 | 0.6 ppb | 0.004 ppb | 10 ppb | Above the health goal150x the health goal |
| Chromium-6average · range 5.3 to 10 · San Marino wells · 2025 report, page 6 | 8.6 ppb | 0.02 ppb | 10 ppb | Above the health goal430x the health goal |
| Tetrachloroethylene (PCE)average · range ND to 2.1 · San Marino wells · 2025 report, page 7 | 0.62 ppb | 0.06 ppb | 5 ppb | Above the health goal10x the health goal |
| Uraniumaverage · range 2.09 to 5.66 · printed as 2.2 pCi/L · San Marino wells · 2025 report, page 7 | 3.28 ppb | 0.6 ppb | 30 ppb | Above the health goal5.5x the health goal |
| Bariumaverage · range 0.02 to 0.02 · San Marino wells · 2025 report, page 6 | 0.02 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloraminehighest running annual average · range 1.1 to 3.1 · Distribution system · 2025 report, page 5 | 2.6 ppm | None set | 4 ppm | Below the legal limit |
| Chlorideaverage · range 8.2 to 17 · San Marino wells · 2025 report, page 8 | 13 ppm | — | 250 ppm guideline | Within the guideline |
| Chromium (total)average · range 5.4 to 10 · San Marino wells · 2025 report, page 6 | 8.2 ppb | None set | 100 ppb | Below the legal limit |
| Copper90th percentile of 30 homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 3 | 0.23 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range ND to 5.4 · Distribution system · 2025 report, page 5 | 2.7 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 2 to 34 · Distribution system · 2025 report, page 5 | 19 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.8 to 1 · San Marino wells · 2025 report, page 6 | 0.9 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of 30 homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 3 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)average · range 1 to 4.7 · San Marino wells · 2025 report, page 7 | 3.4 ppm | 10 ppm | 10 ppm | Below the health goal |
| Perchlorateaverage · range ND to 1.2 · San Marino wells · 2025 report, page 7 | 0.3 ppb | 1 ppb | 6 ppb | Below the health goal |
| Sulfateaverage · range 16 to 41 · San Marino wells · 2025 report, page 8 | 23 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 210 to 250 · San Marino wells · 2025 report, page 8 | 229 ppm | — | 500 ppm guideline | Within the guideline |
| Trichloroethylene (TCE)average · range ND to 4.4 · San Marino wells · 2025 report, page 7 | 1.3 ppb | 1.7 ppb | 5 ppb | Below the health goal |
| Sodiumaverage · San Marino wells · 2025 report, page 9 | 26 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 Cal/Am Water Company - San Marino’s water between May 2023 and Jan 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium91.9 ppbFound in 4 of 16 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.
Industrial chemicals and pesticides
Found: Tetrachloroethylene (PCE)
What removes it: Carbon block or RO.
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