Disinfection byproducts · 2024
Perchlorate in Contra Costa Water District, CA tap water
Contra Costa Water District, CA's 2024 Perchlorate measurement is below the federal limit of 6 UG/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Highest single sample Distribution | 4.6 UG/L | 6 UG/L MCL |
Average Distribution | 4.6 UG/L | 6 UG/L MCL |
Highest single sample Entry point | Not detected UG/L | 6 UG/L MCL |
Highest single sample Source water | Not detected UG/L | 6 UG/L MCL |
Verbatim from Contra Costa Water District, CA's 2024 Consumer Confidence Report — source document ↗
About Perchlorate
A chemical used in rocket fuel and fireworks that can also form during disinfection.
Can interfere with thyroid hormone production; has no national enforceable limit but is regulated in some states.
How Contra Costa Water District, CA compares
5 of the 189 systems measuring Perchlorate on The Water Map have it at or above the federal limit:
Nearby systems also reporting Perchlorate:
People also ask
+Is there Perchlorate in Contra Costa Water District, CA tap water?
Yes — Contra Costa Water District, CA's 2024 Consumer Confidence Report lists Perchlorate at 4.6 UG/L. Contra Costa Water District, CA's 2024 Perchlorate measurement is below the federal limit of 6 UG/L (MCL).
+What's the federal limit for Perchlorate in drinking water?
The federal MCL for Perchlorate is 6 UG/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is Perchlorate?
A chemical used in rocket fuel and fireworks that can also form during disinfection. Can interfere with thyroid hormone production; has no national enforceable limit but is regulated in some states.
+Which other U.S. cities have Perchlorate over the federal limit?
5 of the 189 systems on The Water Map measuring Perchlorate report it at or above the federal limit. Examples include Rialto, City of, CA, Rialto, City of, CA, Rialto, City of, CA.
+Where does this Perchlorate measurement come from?
This page reproduces the Perchlorate entry from the 2024 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/2024/source.