Metals
Thallium in U.S. tap water
27 public water systems across 9 U.S. states report Thallium in their annual Consumer Confidence Report. 1 sit at or above the federal limit.
At or above the federal limit (1)
| Water system | Measured | vs. limit |
|---|---|---|
| St George, UT 2024 annual report | 0–0.5 ug/L | 1.0× the limit |
Within the federal limit (26)
| Water system | Measured |
|---|---|
| Chandler, AZ 2024 annual report | 0–0.15 ug/L |
| West Valley City, UT 2024 annual report | 0.05 ug/L |
| City of Hialeah, FL 2023 annual report | 0.02–0.02 ug/L |
| City of Homestead, FL 2023 annual report | 0.02–0.02 ug/L |
| City of North Miami Beach, FL 2023 annual report | 0.02–0.02 ug/L |
| Miami Dade, FL 2023 annual report | 0.02–0.02 ug/L |
| Salt Lake City, UT 2024 annual report | 0.00002 |
| Birmingham, AL 2024 annual report | Not detected |
| City of Hampton, VA 2024 annual report | Not detected ug/L |
| City of Newport News, VA 2025 annual report | Not detected ug/L |
| City of Poquoson, VA 2025 annual report | Not detected ug/L |
| City of Poquoson, VA 2024 annual report | Not detected ug/L |
| Cleveland, OH 2024 annual report | Not detected |
| Columbus, OH 2025 annual report | Not detected |
| Hampton, VA 2025 annual report | Not detected ug/L |
| High Point, NC 2024 annual report | Not detected ug/L |
| James City County, VA 2025 annual report | Not detected ug/L |
| James City County, VA 2024 annual report | Not detected ug/L |
| Mobile, AL 2024 annual report | Not detected |
| Montgomery, AL 2024 annual report | Not detected |
| Nashville, TN 2023 annual report | Not detected |
| Newport News, VA 2024 annual report | Not detected ug/L |
| Plano, TX 2024 annual report | 0–0 ug/L |
| West Jordan, UT 2024 annual report | Not detected ug/L |
| York County, VA 2024 annual report | Not detected ug/L |
| York County, VA 2025 annual report | Not detected ug/L |
Frequently asked
+What is Thallium?
Thallium is a contaminant some U.S. public water utilities measure and report in their annual Consumer Confidence Report.
+What is the federal limit for Thallium in drinking water?
The federal MCL for Thallium is 0.002 . 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 Thallium over the federal limit?
1 of the 27 public water systems on The Water Map report Thallium at or above its federal limit, spanning 9 U.S. states. The full list is on this page.
+How can I check if Thallium 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 Thallium.