Physical & aggregate · 2024
Hardness in Ontario, CA tap water
Ontario, CA's 2024 report shows Hardness detected, but the EPA has not set an enforceable federal limit for it.
The measurement
| Statistic | Value | Federal limit |
|---|---|---|
Reported level Purchased Groundwater CDA 1 (870 Zone) | 148 mg/L | None set |
Reported level Local Groundwater | 124 mg/L | None set |
Reported level Purchased Groundwater JCSD (870 Zone) | 200 mg/L | None set |
Reported level Purchased Groundwater CDA 2 (1110 Zone) | 144 mg/L | None set |
Reported level Imported Water (WFA w/ SAWCO) | 119 mg/L | None set |
Verbatim from Ontario, CA's 2024 Consumer Confidence Report — source document ↗
About Hardness
A measure of dissolved calcium and magnesium minerals.
Not federally regulated for health; affects scaling, soap use, and taste.
How Ontario, CA compares
4 of the 124 systems measuring Hardness on The Water Map have it at or above the federal limit:
Nearby systems also reporting Hardness:
People also ask
+Is there Hardness in Ontario, CA tap water?
Yes — Ontario, CA's 2024 Consumer Confidence Report lists Hardness at 200 mg/L. Ontario, CA's 2024 report shows Hardness detected, but the EPA has not set an enforceable federal limit for it.
+What's the federal limit for Hardness in drinking water?
The EPA has not set an enforceable federal limit for Hardness. Utilities still report any measured levels in their annual Consumer Confidence Report.
+What is Hardness?
A measure of dissolved calcium and magnesium minerals. Not federally regulated for health; affects scaling, soap use, and taste.
+Which other U.S. cities have Hardness over the federal limit?
4 of the 124 systems on The Water Map measuring Hardness report it at or above the federal limit. Examples include Pomona, CA, Burbank, CA, San Diego, CA.
+Where does this Hardness measurement come from?
This page reproduces the Hardness entry from the 2024 Consumer Confidence Report published by the Ontario, 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/2024/source.