Disinfection byproducts · 2026
Perchlorate in Rialto, City of, CA tap water
Rialto, City of, CA's 2026 Consumer Confidence Report shows Perchlorate at or above the federal limit (6 UG/L MCL). Measured value is 2.5× the threshold.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Entry point | 7.122988505747127 UG/L | 6 UG/L MCL |
Average Source water | 15.137142857142855 UG/L | 6 UG/L MCL |
Highest single sample Entry point | 40 UG/L | 6 UG/L MCL |
Average Distribution | 3.481818181818182 UG/L | 6 UG/L MCL |
Highest single sample Distribution | 11 UG/L | 6 UG/L MCL |
Highest single sample Source water | 110 UG/L | 6 UG/L MCL |
Verbatim from Rialto, City of, CA's 2026 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 Rialto, 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 Rialto, City of, CA tap water?
Yes — Rialto, City of, CA's 2026 Consumer Confidence Report lists Perchlorate at 15.137142857142855 UG/L. Rialto, City of, CA's 2026 Consumer Confidence Report shows Perchlorate at or above the federal limit (6 UG/L MCL). Measured value is 2.5× the threshold.
+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 2026 Consumer Confidence Report published by the Rialto, 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/rialto/2026/source.