Metals · 2025
Chromium, Hexavalent in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2025 Chromium, Hexavalent measurement is below the federal limit of 10 UG/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Entry point | 0.2 UG/L | 10 UG/L MCL |
Average Source water | 0.16 UG/L | 10 UG/L MCL |
Highest single sample Source water | 0.16 UG/L | 10 UG/L MCL |
Highest single sample Entry point | 0.2 UG/L | 10 UG/L MCL |
Verbatim from Contra Costa Water District, CA's 2025 Consumer Confidence Report — source document ↗
About Chromium, Hexavalent
Hexavalent chromium ('chromium-6') — the more toxic form of chromium.
A known carcinogen by inhalation; regulated nationally only within the total-chromium limit, with stricter limits in some states.
How Contra Costa Water District, CA compares
5 of the 178 systems measuring Chromium, Hexavalent on The Water Map have it at or above the federal limit:
Nearby systems also reporting Chromium, Hexavalent:
People also ask
+Is there Chromium, Hexavalent in Contra Costa Water District, CA tap water?
Yes — Contra Costa Water District, CA's 2025 Consumer Confidence Report lists Chromium, Hexavalent at 0.2 UG/L. Contra Costa Water District, CA's 2025 Chromium, Hexavalent measurement is below the federal limit of 10 UG/L (MCL).
+What's the federal limit for Chromium, Hexavalent in drinking water?
The federal MCL for Chromium, Hexavalent is 10 UG/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is Chromium, Hexavalent?
Hexavalent chromium ('chromium-6') — the more toxic form of chromium. A known carcinogen by inhalation; regulated nationally only within the total-chromium limit, with stricter limits in some states.
+Which other U.S. cities have Chromium, Hexavalent over the federal limit?
5 of the 178 systems on The Water Map measuring Chromium, Hexavalent report it at or above the federal limit. Examples include Santa Rosa, CA, Diablo Water District, CA, Golden State Water Company, CA.
+Where does this Chromium, Hexavalent measurement come from?
This page reproduces the Chromium, Hexavalent entry from the 2025 Consumer Confidence Report published by the Contra Costa Water District, 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/contra-costa-water-district/2025/source.