Metals
Thallium in U.S. tap water
61 public water systems across 10 U.S. states report Thallium in their annual Consumer Confidence Report. 3 sit at or above the federal limit.
61
systems measuring
3
over the limit
10
states represented
At or above the federal limit (3)
| Water system | Measured | vs. limit |
|---|---|---|
| Hialeah, FL 2023 annual report | 0–0.009 mg/L | 4.5× the limit |
| Winton Water & Sanitary Dist — Winton, Ca, CA 2023 annual report | 5 ug/L | 2.5× the limit |
| Gonzales, City of — Gonzales, Ca, CA 2022 annual report | 2 ug/L | 1.0× the limit |
Approaching the limit (3)
| Water system | Measured | vs. limit |
|---|---|---|
| City of Paso Robles Water Division — Paso Robles, Ca, CA 2023 annual report | 0–1.8 ug/L | 0.9× the limit |
| Santa Ynez River Water Cons. Dist. Id#1 — Santa Ynez, Ca, CA 2023 annual report | 0–1.6 ug/L | 0.8× the limit |
| Solvang Water Division — Solvang, Ca, CA 2023 annual report | 0–1.6 ug/L | 0.8× the limit |
Within the federal limit (55)
| Water system | Measured |
|---|---|
| Camp Williams-resort Water — Manhattan Beach, Ca, CA 2020 annual report | 1 ug/L |
| Camp Williams-resort Water — Manhattan Beach, Ca, CA 2021 annual report | 1 ug/L |
| Loma Linda, City of — Loma Linda, Ca, CA 2023 annual report | 0.4–0.55 ug/L |
| St George, UT 2024 annual report | 0–0.5 ug/L |
| Chandler, AZ 2024 annual report | 0.15 ug/L |
| Peoria, AZ 2024 annual report | 0.12 ug/L |
| West Valley City, UT 2024 annual report | 0.05 ug/L |
| City of Hialeah, FL 2023 annual report | 0.01–0.02 ug/L |
| City of North Miami Beach, FL 2023 annual report | 0.01–0.02 ug/L |
| Miami Dade, FL 2023 annual report | 0.01–0.02 ug/L |
| Salt Lake City, UT 2024 annual report | 0.00002 mg/L |
| Antelope Valley East Kern Water Agency — Palmdale, Ca, CA 2023 annual report | Not detected ug/L |
| Antelope Valley East Kern Water Agency — Palmdale, Ca, CA 2020 annual report | Not detected ug/L |
| Antelope Valley East Kern Water Agency — Palmdale, Ca, CA 2021 annual report | Not detected ug/L |
| Antelope Valley East Kern Water Agency — Palmdale, Ca, CA 2022 annual report | Not detected ug/L |
| Birmingham, AL 2024 annual report | Not detected mg/L |
| Boron Csd — Boron, Ca, CA 2022 annual report | Not detected ug/L |
| 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 2024 annual report | Not detected ug/L |
| City of Poquoson, VA 2025 annual report | Not detected ug/L |
| City of West Sacramento — West Sacramento, Ca, CA 2022 annual report | Not detected ug/L |
| Cleveland, OH 2024 annual report | Not detected mg/L |
| Columbus, OH 2025 annual report | Not detected mg/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2023 annual report | Not detected ug/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2020 annual report | Not detected ug/L |
| Covina Irrigating Co. — West Covina, Ca, CA 2021 annual report | Not detected ug/L |
| Foothill Municipal Water Dist. — La Canada Flintridge, Ca, CA 2023 annual report | Not detected ug/L |
| Garland, TX 2024 annual report | 0–0 ug/L |
| 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 |
| Lukins Brothers Water Company — South Lake Tahoe, Ca, CA 2022 annual report | Not detected ug/L |
| Mobile, AL 2024 annual report | Not detected ug/L |
| Mojave Pud — Mojave, Ca, CA 2023 annual report | Not detected ug/L |
| Montgomery, AL 2024 annual report | Not detected mg/L |
| Nashville, TN 2023 annual report | Not detected mg/L |
| Newport News, VA 2024 annual report | Not detected ug/L |
| North Gualala Water Company — Gualala, Ca, CA 2023 annual report | Not detected ug/L |
| North Tahoe Pud - Main — Tahoe Vista, Ca, CA 2021 annual report | Not detected mg/L |
| Plano, TX 2024 annual report | 0–0 ug/L |
| South Tahoe Pud - Main — South Lake Tahoe, Ca, CA 2023 annual report | Not detected ug/L |
| Thermalito Water & Sewer Dist — Oroville, Ca, CA 2023 annual report | Not detected ug/L |
| Three Valleys MWD — Claremont, Ca, CA 2023 annual report | Not detected ug/L |
| Thunderbird Cwd — Apple Valley, Ca, CA 2023 annual report | 0 ug/L |
| West Jordan, UT 2024 annual report | Not detected ug/L |
| Westside Park Mutual Water — Palmdale, Ca, CA 2023 annual report | Not detected ug/L |
| White Fence Farms Mwc No. 1 — Palmdale, Ca, CA 2021 annual report | Not detected ug/L |
| White Fence Farms Mwc No. 1 — Palmdale, Ca, CA 2023 annual report | Not detected ug/L |
| White Fence Farms Mwc No. 1 — Palmdale, Ca, CA 2020 annual report | Not detected ug/L |
Showing 50 of 55. The full list is in the JSON API.
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 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 Thallium over the federal limit?
3 of the 61 public water systems on The Water Map report Thallium at or above its federal limit, spanning 10 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.