Metals · 2025
Copper in California Water Service - San Mateo, CA tap water
California Water Service - San Mateo, CA's 2025 Copper measurement is below the federal limit of 1300 UG/L (Al).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
90th percentile Distribution | 40.13 UG/L | 1300 UG/L Al |
Average Distribution | 30.298000000000002 UG/L | None set |
Highest single sample Distribution | 186 UG/L | None set |
Verbatim from California Water Service - San Mateo, CA's 2025 Consumer Confidence Report — source document ↗
About Copper
A metal that enters water from corroding household plumbing.
Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.
How California Water Service - San Mateo, CA compares
5 of the 442 systems measuring Copper on The Water Map have it at or above the federal limit:
Nearby systems also reporting Copper:
People also ask
+Is there Copper in California Water Service - San Mateo, CA tap water?
Yes — California Water Service - San Mateo, CA's 2025 Consumer Confidence Report lists Copper at 40.13 UG/L. California Water Service - San Mateo, CA's 2025 Copper measurement is below the federal limit of 1300 UG/L (Al).
+What's the federal limit for Copper in drinking water?
The federal Al for Copper is 1300 UG/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is Copper?
A metal that enters water from corroding household plumbing. Short-term exposure causes stomach distress; long-term exposure can damage the liver and kidneys.
+Which other U.S. cities have Copper over the federal limit?
5 of the 442 systems on The Water Map measuring Copper report it at or above the federal limit. Examples include Town of Denton, MD, High Point, NC, Anchorage, AK.
+Where does this Copper measurement come from?
This page reproduces the Copper entry from the 2025 Consumer Confidence Report published by the California Water Service - San Mateo, 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/california-water-service-san-mateo/2025/source.