Disinfection byproducts · 2025
Perchlorate in San Diego, City of, CA tap water
San Diego, City of, CA's 2025 Perchlorate measurement is below the federal limit of 6 UG/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Source water | 0.515 UG/L | 6 UG/L MCL |
Average Other | 0.36999999999999994 UG/L | 6 UG/L MCL |
Highest single sample Source water | 1.2 UG/L | 6 UG/L MCL |
Highest single sample Other | 0.61 UG/L | 6 UG/L MCL |
Highest single sample Entry point | 0.58 UG/L | 6 UG/L MCL |
Average Entry point | 0.36000000000000004 UG/L | 6 UG/L MCL |
Verbatim from San Diego, City of, CA's 2025 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 San Diego, City of, CA compares
5 of the 193 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 San Diego, City of, CA tap water?
Yes — San Diego, City of, CA's 2025 Consumer Confidence Report lists Perchlorate at 0.515 UG/L. San Diego, City of, CA's 2025 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 193 systems on The Water Map measuring Perchlorate report it at or above the federal limit. Examples include Rialto, CA, Rialto, City of, CA, Rialto, City of, CA.
+Where does this Perchlorate measurement come from?
This page reproduces the Perchlorate entry from the 2025 Consumer Confidence Report published by the San Diego, City of, 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/san-diego/2025/source.