Physical & aggregate · 2026
Hardness in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2026 report shows Hardness detected, but the EPA has not set an enforceable federal limit for it.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Source water | 65 MG/L | None set |
Highest single sample Source water | 65 MG/L | None set |
Verbatim from Contra Costa Water District, CA's 2026 Consumer Confidence Report — source document ↗
About Hardness
A measure of dissolved calcium and magnesium minerals.
Not federally regulated for health; affects scaling, soap use, and taste.
How Contra Costa Water District, CA compares
Nearby systems also reporting Hardness:
People also ask
+Is there Hardness in Contra Costa Water District, CA tap water?
Yes — Contra Costa Water District, CA's 2026 Consumer Confidence Report lists Hardness at 65 MG/L. Contra Costa Water District, CA's 2026 report shows Hardness detected, but the EPA has not set an enforceable federal limit for it.
+What's the federal limit for Hardness in drinking water?
The EPA has not set an enforceable federal limit for Hardness. Utilities still report any measured levels in their annual Consumer Confidence Report.
+What is Hardness?
A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
+Where does this Hardness measurement come from?
This page reproduces the Hardness entry from the 2026 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/2026/source.