Physical & aggregate · 2025

Hardness in Contra Costa Water District, CA tap water

Detected — no federal limit

Contra Costa Water District, CA's 2025 report shows Hardness detected, but the EPA has not set an enforceable federal limit for it.

The measurement

StatisticValue
Average
Entry point
74.6 MG/L
Highest single sample
Source water
136 MG/L
Average
Source water
81.17999999999999 MG/L
Highest single sample
Entry point
86.8 MG/L

Verbatim from Contra Costa Water District, CA's 2025 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 2025 Consumer Confidence Report lists Hardness at 81.17999999999999 MG/L. Contra Costa Water District, CA's 2025 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 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.

Full report
All Contra Costa Water District, CA water-quality data →
Every contaminant measured in the 2025 report.
Contaminant pillar
Hardness across the U.S. →
Every public water system measuring Hardness, ranked.