Disinfection byproducts · 2026
HAA5 in City of Hayward, CA tap water
City of Hayward, CA's 2026 HAA5 measurement is below the federal limit of 60 UG/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Highest single sample Distribution | 24.1 UG/L | 60 UG/L MCL |
Average Distribution | 22.025 UG/L | 60 UG/L MCL |
Verbatim from City of Hayward, CA's 2026 Consumer Confidence Report — source document ↗
About HAA5
Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter.
Long-term exposure above the federal limit is associated with an increased cancer risk.
How City of Hayward, CA compares
5 of the 439 systems measuring HAA5 on The Water Map have it at or above the federal limit:
Nearby systems also reporting HAA5:
People also ask
+Is there HAA5 in City of Hayward, CA tap water?
Yes — City of Hayward, CA's 2026 Consumer Confidence Report lists HAA5 at 22.025 UG/L. City of Hayward, CA's 2026 HAA5 measurement is below the federal limit of 60 UG/L (MCL).
+What's the federal limit for HAA5 in drinking water?
The federal MCL for HAA5 is 60 UG/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is HAA5?
Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. Long-term exposure above the federal limit is associated with an increased cancer risk.
+Which other U.S. cities have HAA5 over the federal limit?
5 of the 439 systems on The Water Map measuring HAA5 report it at or above the federal limit. Examples include Albuquerque, NM, Columbus, OH, Hollywood, FL.
+Where does this HAA5 measurement come from?
This page reproduces the HAA5 entry from the 2026 Consumer Confidence Report published by the City of Hayward, CA water utility — the annual drinking-water report every U.S. utility is required by federal law to publish. The original source document is archived at /water/ca/hayward/2026/source.