Radionuclides · 2025
Radon in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2025 Consumer Confidence Report tested for Radon and reported no detectable amount.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Highest single sample Entry point | Not detected PCI/L | None set |
Highest single sample Source water | Not detected PCI/L | None set |
Verbatim from Contra Costa Water District, CA's 2025 Consumer Confidence Report — source document ↗
About Radon
A naturally occurring radioactive gas that can dissolve into groundwater.
No enforceable federal limit in drinking water yet; inhalation of released radon raises lung-cancer risk.
How Contra Costa Water District, CA compares
1 of the 20 systems measuring Radon on The Water Map have it at or above the federal limit:
Nearby systems also reporting Radon:
People also ask
+Is there Radon in Contra Costa Water District, CA tap water?
Contra Costa Water District, CA's 2025 Consumer Confidence Report tested for Radon and found no detectable amount.
+What's the federal limit for Radon in drinking water?
The EPA has not set an enforceable federal limit for Radon. Utilities still report any measured levels in their annual Consumer Confidence Report.
+What is Radon?
A naturally occurring radioactive gas that can dissolve into groundwater. No enforceable federal limit in drinking water yet; inhalation of released radon raises lung-cancer risk.
+Which other U.S. cities have Radon over the federal limit?
1 of the 20 systems on The Water Map measuring Radon report it at or above the federal limit. Examples include Santa Rosa, CA.
+Where does this Radon measurement come from?
This page reproduces the Radon 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.