We read 14 results from Alameda County Water District’s 2025 water quality report. No results over a legal limit; 2 above a health goal or guideline.
Serves about 344,000 people · Water system ID CA0110001 · 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 |
|---|---|---|---|---|
| Chromium-6highest measured · range 0.12 to 0.26 · Desalination and blending facilities · 2025 report, page 4 | 0.26 ppb | 0.02 ppb | 10 ppb | Above the health goal13x the health goal |
| pHaverage · range 8.5 to 9.3 · Purchased San Francisco water, highest of 4 sources · 2025 report, page 3 | 9 | — | — | Outside the normal rangeAlkaline water can leave scale |
| Bromatehighest running annual average · range ND to 2.3 · Treated surface water · 2025 report, page 3 | Not detected | 0.1 ppb | 10 ppb | Not detected |
| Chloramineaverage · range ND to 3.4 · Distribution system · 2025 report, page 3 | 2.1 ppm | None set | 4 ppm | Below the legal limit |
| Chlorideaverage · range 32 to 140 · Treated surface water, highest of 4 sources · 2025 report, page 3 | 66 ppm | — | 250 ppm guideline | Within the guideline |
| Copper90th percentile of 58 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 3 | 0.1 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 2.6 to 43 · Distribution system · 2025 report, page 3 | 32 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 3.5 to 84 · Distribution system · 2025 report, page 3 | 41.8 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range ND to 0.96 · Treated water · 2025 report, page 3 | 0.77 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of 58 homes tested, 1 over the action level · sampled 2024 · Customer taps · 2025 report, page 3 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Sulfateaverage · range 32 to 51 · Blended water, highest of 4 sources · 2025 report, page 3 | 38 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 170 to 380 · Treated surface water, highest of 4 sources · 2025 report, page 3 | 255 ppm | — | 500 ppm guideline | Within the guideline |
| Hardnessaverage · range 7.02 to 9.36 · Blended water, highest of 4 sources · 2025 report, page 3 | 8.07 gpg (138 ppm) | — | — | Hard |
| Sodiumaverage · range 36 to 94 · Treated surface water, highest of 4 sources · 2025 report, page 3 | 60 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.
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.
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