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.
Uranium by state
Every state where a public water system reports Uranium in its annual report, ranked by systems at or above the federal limit.
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.
+Which states report the most Uranium in their drinking water?
Of the systems on The Water Map, California (1 system at or above the limit), Pennsylvania (1 system at or above the limit) report the most Uranium exceedances. The state-by-state table on this page lists every state.
+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.