Physical & aggregate
pH in U.S. tap water
370 public water systems across 23 U.S. states report pH in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
What it is
A measure of how acidic or basic the water is.
Why it's regulated
Regulated only as a secondary standard; very low or high pH can corrode pipes or affect taste.
Frequently asked
+What is pH?
A measure of how acidic or basic the water is. Regulated only as a secondary standard; very low or high pH can corrode pipes or affect taste.
+What is the federal limit for pH in drinking water?
The federal Public health goal for pH is 6.5 . The EPA enforces this against the regulated reporting statistic (typically a running annual average or 90th percentile), not a single-sample spike.
+How many U.S. water systems have pH over the federal limit?
Zero of the 370 public water systems in The Water Map dataset currently report pH at or above its federal limit.
+How can I check if pH 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 pH.