Inorganic chemicals
Sulfate in U.S. tap water
323 public water systems across 30 U.S. states report Sulfate in their annual Consumer Confidence Report. None currently sit at or above the federal limit.
What it is
A naturally occurring mineral from rock and soil.
Why it's regulated
No health-based federal limit; high levels can have a laxative effect and a bitter taste.
Within the federal limit (1)
| Water system | Measured |
|---|---|
| Stamford, CT 2024 annual report | 35 mg/L |
Frequently asked
+What is Sulfate?
A naturally occurring mineral from rock and soil. No health-based federal limit; high levels can have a laxative effect and a bitter taste.
+What is the federal limit for Sulfate in drinking water?
The federal Secondary MCL for Sulfate is 250 mg/L. 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 Sulfate over the federal limit?
Zero of the 323 public water systems in The Water Map dataset currently report Sulfate at or above its federal limit.
+How can I check if Sulfate 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 Sulfate.