Metals · 2024
Magnesium in Ontario, CA tap water
Ontario, CA's 2024 report shows Magnesium 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) | 9.1 mg/L | None set |
Reported level Imported Water (WFA w/ SAWCO) | 9.4 mg/L | None set |
Reported level Local Groundwater | 6.8 mg/L | None set |
Reported level Purchased Groundwater CDA 2 (1110 Zone) | 8 mg/L | None set |
Reported level Purchased Groundwater JCSD (870 Zone) | 8.6 mg/L | None set |
Verbatim from Ontario, CA's 2024 Consumer Confidence Report — source document ↗
About Magnesium
A naturally occurring mineral that contributes to water hardness.
Not federally regulated for health; affects scaling and taste.
How Ontario, CA compares
3 of the 111 systems measuring Magnesium on The Water Map have it at or above the federal limit:
Nearby systems also reporting Magnesium:
People also ask
+Is there Magnesium in Ontario, CA tap water?
Yes — Ontario, CA's 2024 Consumer Confidence Report lists Magnesium at 9.4 mg/L. Ontario, CA's 2024 report shows Magnesium detected, but the EPA has not set an enforceable federal limit for it.
+What's the federal limit for Magnesium in drinking water?
The EPA has not set an enforceable federal limit for Magnesium. Utilities still report any measured levels in their annual Consumer Confidence Report.
+What is Magnesium?
A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and taste.
+Which other U.S. cities have Magnesium over the federal limit?
3 of the 111 systems on The Water Map measuring Magnesium report it at or above the federal limit. Examples include Pomona, CA, Burbank, CA, Vancouver, WA.
+Where does this Magnesium measurement come from?
This page reproduces the Magnesium 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.