Radionuclides
Uranium in U.S. tap water
772 public water systems across 20 U.S. states report Uranium in their annual Consumer Confidence Report. 2 sit at or above the federal limit.
What it is
A naturally occurring radioactive metal from erosion of natural deposits.
Why it's regulated
Long-term exposure above the federal limit can damage the kidneys and increase cancer risk.
At or above the federal limit (2)
| Water system | Measured | vs. limit |
|---|---|---|
| Philadelphia, PA 2023 annual report | 226 ug/L | 7.5× the limit |
| Cal Am - Bass Lake — Sacramento, Ca, CA 2023 annual report | 34–45 ug/L | 1.5× the limit |
Approaching the limit (1)
| Water system | Measured | vs. limit |
|---|---|---|
| Edmond, OK 2024 annual report | 28.8 ug/L | 1.0× the limit |
Within the federal limit (151)
Showing 50 of 151. The full list is in the JSON API.
Frequently asked
+What is Uranium?
A naturally occurring radioactive metal from erosion of natural deposits. Long-term exposure above the federal limit can damage the kidneys and increase cancer risk.
+What is the federal limit for Uranium in drinking water?
The federal MCLG for Uranium is 0 ug/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 Uranium over the federal limit?
2 of the 772 public water systems on The Water Map report Uranium at or above its federal limit, spanning 20 U.S. states. The full list is on this page.
+How can I check if Uranium 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 Uranium.