Drinking water quality · 2025
· Verified
What's in City of Hayward, CA tap water
13 contaminants were measured in the City of Hayward, CA water system's 2025 annual report. Each is shown below against its federal limit.
- Reporting year
- 2025
- Contaminants measured
- 13
- Over federal limit
- 0
- Approaching the limit
- 0
- Service area
- CA
Where your water comes from · EPA SDWIS
City of Hayward, CA's drinking water comes from ground water, drawn from 4 sources.
Source
- WELL A - POLICE STATION-EMERGENCY STANBY
- WELL C - PEPSI WELL - EMERGENCY STANDBY
- WELL E - EMERGENCY STANDBY
- WELL D - AIRPORT WELL-EMERGENCY STANDBY
Treatment
Distribution
Also buys water from SAN FRANCISCO REGIONAL WATER SYSTEM.
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 45.646875 UG/LAverageDistribution | 80 UG/LMCL | Within the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 31.0146875 UG/LAverageDistribution | 60 UG/LMCL | Within the limit |
| BromoformA trihalomethane disinfection byproduct. | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| BromodichloromethaneA trihalomethane disinfection byproduct. | 2.5628125 UG/LAverageDistribution | None set | Detected — no federal limit |
| ChloroformA trihalomethane formed when chlorine reacts with organic matter in water. | 42.840625 UG/LAverageDistribution | None set | Detected — no federal limit |
| DibromochloromethaneA trihalomethane disinfection byproduct. | 0.639375 UG/LAverageDistribution | None set | Detected — no federal limit |
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | 5 UG/L90th percentileDistribution | 15 UG/LAl | Within the limit |
| CopperA metal that enters water from corroding household plumbing. | 55.05 UG/L90th percentileDistribution | 1300 UG/LAl | Within the limit |
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Dbaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Mbaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Mcaa | Not detected UG/LHighest single sampleDistribution | None set | None detected |
| Dcaa | 16.375 UG/LAverageDistribution | None set | Detected — no federal limit |
| Tcaa | 14.6465625 UG/LAverageDistribution | None set | Detected — no federal limit |
People also ask about City of Hayward, CA's water
+Is City of Hayward, CA tap water safe to drink in 2025?
Every one of the 13 contaminants measured in City of Hayward, CA's 2025 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in City of Hayward, CA tap water?
13 contaminants were measured in City of Hayward, CA's 2025 Consumer Confidence Report, spanning disinfection byproducts, other, and metals. 4 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Where does the data on this page come from?
Every value is transcribed from City of Hayward, CA's 2025 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is City of Hayward, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2025 report; a new report will replace it once the utility publishes its next annual update.