Metals
Magnesium in U.S. tap water
362 public water systems across 20 U.S. states report Magnesium in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
What it is
A naturally occurring mineral that contributes to water hardness.
Why it's regulated
Not federally regulated for health; affects scaling and taste.
Frequently asked
+What is Magnesium?
A naturally occurring mineral that contributes to water hardness. Not federally regulated for health; affects scaling and taste.
+Does Magnesium have a federal limit in drinking water?
Magnesium does not have an enforceable federal MCL. Utilities still report any measured levels in their annual Consumer Confidence Report.
+How many U.S. water systems have Magnesium over the federal limit?
Zero of the 362 public water systems in The Water Map dataset currently report Magnesium at or above its federal limit.
+How can I check if Magnesium is in my city's tap water?
Search your city on The Water Map (https://www.thewatermap.com/) or browse the list on this page. Every U.S. public water utility is required to publish an annual Consumer Confidence Report that lists every contaminant it measured, including Magnesium.