Metals · 2026
Magnesium in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2026 report shows Magnesium detected, but the EPA has not set an enforceable federal limit for it.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Highest single sample Source water | 8.5 MG/L | None set |
Highest single sample Entry point | 10.7 MG/L | None set |
Average Source water | 8.5 MG/L | None set |
Average Entry point | 10.212499999999999 MG/L | None set |
Verbatim from Contra Costa Water District, CA's 2026 Consumer Confidence Report — source document ↗
About Magnesium
A naturally occurring mineral that contributes to water hardness.
Not federally regulated for health; affects scaling and taste.
How Contra Costa Water District, CA compares
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People also ask
+Is there Magnesium in Contra Costa Water District, CA tap water?
Yes — Contra Costa Water District, CA's 2026 Consumer Confidence Report lists Magnesium at 10.212499999999999 MG/L. Contra Costa Water District, CA's 2026 report shows Magnesium detected, but the EPA has not set an enforceable federal limit for it.
+What's the federal limit for Magnesium in drinking water?
The EPA has not set an enforceable federal limit for Magnesium. Utilities still report any measured levels in their annual Consumer Confidence Report.
+What is Magnesium?
A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and taste.
+Where does this Magnesium measurement come from?
This page reproduces the Magnesium 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.