Metals · 2026
Arsenic in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2026 Consumer Confidence Report tested for Arsenic and reported no detectable amount.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Highest single sample Source water | Not detected UG/L | 10 UG/L MCL |
Verbatim from Contra Costa Water District, CA's 2026 Consumer Confidence Report — source document ↗
About Arsenic
A naturally occurring element that also enters water from industry and agriculture.
A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
How Contra Costa Water District, CA compares
5 of the 287 systems measuring Arsenic on The Water Map have it at or above the federal limit:
Nearby systems also reporting Arsenic:
People also ask
+Is there Arsenic in Contra Costa Water District, CA tap water?
Contra Costa Water District, CA's 2026 Consumer Confidence Report tested for Arsenic and found no detectable amount.
+What's the federal limit for Arsenic in drinking water?
The federal MCL for Arsenic 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 Arsenic?
A naturally occurring element that also enters water from industry and agriculture. A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
+Which other U.S. cities have Arsenic over the federal limit?
5 of the 287 systems on The Water Map measuring Arsenic report it at or above the federal limit. Examples include Albuquerque, NM, Mesa Del Toro Mwc, CA, Beaches Water, MD.
+Where does this Arsenic measurement come from?
This page reproduces the Arsenic 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.