Radionuclides · 2025
Gross Alpha in Ontario Municipal Utilities Company, CA tap water
Ontario Municipal Utilities Company, CA's 2025 Gross Alpha measurement is below the federal limit of 15 PCI/L (MCL).
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Average Source water | 3.3 PCI/L | 15 PCI/L MCL |
Highest single sample Source water | 3.3 PCI/L | 15 PCI/L MCL |
Verbatim from Ontario Municipal Utilities Company, CA's 2025 Consumer Confidence Report — source document ↗
About Gross Alpha
Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances.
Long-term exposure above the federal limit increases cancer risk.
How Ontario Municipal Utilities Company, CA compares
5 of the 246 systems measuring Gross Alpha on The Water Map have it at or above the federal limit:
Nearby systems also reporting Gross Alpha:
People also ask
+Is there Gross Alpha in Ontario Municipal Utilities Company, CA tap water?
Yes — Ontario Municipal Utilities Company, CA's 2025 Consumer Confidence Report lists Gross Alpha at 3.3 PCI/L. Ontario Municipal Utilities Company, CA's 2025 Gross Alpha measurement is below the federal limit of 15 PCI/L (MCL).
+What's the federal limit for Gross Alpha in drinking water?
The federal MCL for Gross Alpha is 15 PCI/L. The EPA enforces this against the regulated reporting statistic (running annual average or 90th percentile), not a single-sample spike.
+What is Gross Alpha?
Gross alpha particle activity — a combined measure of alpha-emitting radioactive substances. Long-term exposure above the federal limit increases cancer risk.
+Which other U.S. cities have Gross Alpha over the federal limit?
5 of the 246 systems on The Water Map measuring Gross Alpha report it at or above the federal limit. Examples include San Diego, City of, CA, Birmingham, AL, Rancho Estates Mutual Water Co., CA.
+Where does this Gross Alpha measurement come from?
This page reproduces the Gross Alpha entry from the 2025 Consumer Confidence Report published by the Ontario Municipal Utilities Company, 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/ontario-municipal-utilities-company/2025/source.