We read 11 results from City of Hayward’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 162,954 people · Water system ID CA0110006 · 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 |
|---|---|---|---|---|
| Chromium-6highest measured · range ND to 0.1 · Source water · 2025 report, page 8 | 0.1 ppb | 0.02 ppb | 10 ppb | Above the health goal5x the health goal |
| Chloraminehighest running annual average · range 2.3 to 3.3 · Distribution system · 2025 report, page 8 | 2.9 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested · printed as 53 ppb · Customer taps · 2025 report, page 8 | 0.05 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 9.6 to 44 · Distribution system · 2025 report, page 8 | 31 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 19 to 64 · Distribution system · 2025 report, page 8 | 46 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.5 to 0.8 · Treated water · 2025 report, page 9 | 0.7 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of homes tested · Customer taps · 2025 report, page 8 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Manganesehighest measured · range ND to 0.0027 · printed as 2.7 ppb · Source water · 2025 report, page 9 | 0.0027 ppm | — | 0.05 ppm guideline | Within the guideline |
| Nitrate (as N)highest measured · range ND to 0.4 · Source water · 2025 report, page 8 | 0.4 ppm | 10 ppm | 10 ppm | Below the health goal |
| Total dissolved solidsaverage · range 24 to 197 · Source water · 2025 report, page 9 | 111 ppm | — | 500 ppm guideline | Within the guideline |
| Turbidity (cloudiness)highest measured · Sunol Valley Water Treatment Plant · 2025 report, page 8 | 0.3 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.
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