Metals
Arsenic in U.S. tap water
787 public water systems across 34 U.S. states report Arsenic in their annual Consumer Confidence Report. 28 sit at or above the federal limit.
787
systems measuring
28
over the limit
34
states represented
What it is
A naturally occurring element that also enters water from industry and agriculture.
Why it's regulated
A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
Federal limit10 ug/L· MCLG
At or above the federal limit (28)
| Water system | Measured | vs. limit |
|---|---|---|
| Lakeside Wd — Lakeside, Ca, CA 2023 annual report | 0–54.2 ug/L | 5.4× the limit |
| Firebaugh City — Firebaugh, Ca, CA 2023 annual report | 4.4–43 ug/L | 4.3× the limit |
| Quartz Hill Water Dist. — Quartz Hill, Ca, CA 2021 annual report | 0–24 ug/L | 2.4× the limit |
| Lancaster Park Mobile Home Park — Lancaster, Ca, CA 2021 annual report | 23 ug/L | 2.3× the limit |
| Chuckawalla Valley State Prison — Blythe, Ca, CA 2022 annual report | 0–17 ug/L | 1.7× the limit |
| Templeton Csd — Templeton, Ca, CA 2023 annual report | 0–17 ug/L | 1.7× the limit |
| Valley State Prison — Chowchilla, Ca, CA 2023 annual report | 5.4–17 ug/L | 1.7× the limit |
| Quartz Hill Water Dist. — Quartz Hill, Ca, CA 2020 annual report | 0–16.2 ug/L | 1.6× the limit |
| Quartz Hill Water Dist. — Quartz Hill, Ca, CA 2022 annual report | 0–13.4 ug/L | 1.3× the limit |
| Hilmar County Water District — Hilmar, Ca, CA 2023 annual report | 1.02–13.2 ug/L | 1.3× the limit |
| Mcfarland, City of — Mcfarland, Ca, CA 2023 annual report | 6.6–13 ug/L | 1.3× the limit |
| Midland, TX 2024 annual report | 0–13 ug/L | 1.3× the limit |
| Petaluma, City of — Petaluma, Ca, CA 2021 annual report | 0–13 ug/L | 1.3× the limit |
| Rohnert Park, City of — Rohnert Park, Ca, CA 2023 annual report | 2.4–13 ug/L | 1.3× the limit |
| San Miguel Community Services District — San Miguel, Ca, CA 2023 annual report | 3–13 ug/L | 1.3× the limit |
| St George, UT 2024 annual report | 1–13 ug/L | 1.3× the limit |
| Rio Cosumnes Correctional Center [sws] — Sacramento, Ca, CA 2023 annual report | 0–12.2 ug/L | 1.2× the limit |
| City of Lathrop — Lathrop, Ca, CA 2023 annual report | 6–12 ug/L | 1.2× the limit |
| Quartz Hill Water Dist. — Quartz Hill, Ca, CA 2023 annual report | 0–12 ug/L | 1.2× the limit |
| Claiborne, MD 2024 annual report | 4.3–11.6 ug/L | 1.2× the limit |
| California Rehabilitation Center - Norco — Norco, Ca, CA 2022 annual report | 0–11 ug/L | 1.1× the limit |
| Kern Valley State Prison — Delano, Ca, CA 2023 annual report | 0–11 ug/L | 1.1× the limit |
| Tulare, City of — Tulare, Ca, CA 2023 annual report | 0–11 ug/L | 1.1× the limit |
| Beaches Water, MD 2024 annual report | 10.9 ug/L | 1.1× the limit |
| Beaver Run Mhp, MD 2024 annual report | 10.6 ug/L | 1.1× the limit |
| Norman, OK 2024 annual report | 10 ug/L | 1.0× the limit |
| Port St Lucie, FL 2024 annual report | 0.01 mg/L | 1.0× the limit |
| Sutter Community S.d. — Sutter, Ca, CA 2023 annual report | 10 ug/L | 1.0× the limit |
Approaching the limit (32)
| Water system | Measured | vs. limit |
|---|---|---|
| Pearland, TX 2024 annual report | 0–9.9 ug/L | 1.0× the limit |
| City of La Palma — La Palma, Ca, CA 2021 annual report | 9.5 ug/L | 0.9× the limit |
| City of Livingston — Livingston, Ca, CA 2023 annual report | 0–9.5 ug/L | 0.9× the limit |
| Arvin Community Services Dist — Arvin, Ca, CA 2022 annual report | 3.8–9.3 ug/L | 0.9× the limit |
| Hughson, City of — Hughson, Ca, CA 2023 annual report | 9.28 ug/L | 0.9× the limit |
| Keyes Community Services Dist. — Keyes, Ca, CA 2023 annual report | 5.95–9.12 ug/L | 0.9× the limit |
| Elsinore Valley MWD — Lake Elsinore, Ca, CA 2022 annual report | 0–9.1 ug/L | 0.9× the limit |
| California City, City of — California City, Ca, CA 2023 annual report | 6–9 ug/L | 0.9× the limit |
| City of Rio Vista — Rio Vista, Ca, CA 2022 annual report | 9 ug/L | 0.9× the limit |
| Cottonwood Water District — Cottonwood, Ca, CA 2022 annual report | 0–9 ug/L | 0.9× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2023 annual report | 9 ug/L | 0.9× the limit |
| Billings, MT 2024 annual report | 8.87 ug/L | 0.9× the limit |
| City of Modesto - Salida — Modesto, Ca, CA 2023 annual report | 8.8 ug/L | 0.9× the limit |
| Chandler, AZ 2024 annual report | 8.6 ug/L | 0.9× the limit |
| Phelan Pinon Hills Csd — Phelan, Ca, CA 2023 annual report | 0–8.6 ug/L | 0.9× the limit |
| Sonoma, City of — Sonoma, Ca, CA 2022 annual report | 6.9–8.5 ug/L | 0.9× the limit |
| Eastside Water Association — Midway City, Ca, CA 2022 annual report | 2.8–8.4 ug/L | 0.8× the limit |
| Scottsdale, AZ 2024 annual report | 8.4 ug/L | 0.8× the limit |
| Victorville, CA 2024 annual report | 8.4 ug/L | 0.8× the limit |
| Mesa, AZ 2024 annual report | 8.37 ug/L | 0.8× the limit |
| Avondale, AZ 2024 annual report | 0–8.3 ug/L | 0.8× the limit |
| Central Ca Womens Facility — Chowchilla, Ca, CA 2023 annual report | 0.0052–0.0083 mg/L | 0.8× the limit |
| Turlock, City of — Turlock, Ca, CA 2023 annual report | 8.3 ug/L | 0.8× the limit |
| Eastside Water Association — Midway City, Ca, CA 2021 annual report | 2.8–8.2 ug/L | 0.8× the limit |
| Lakewood - City, Water Dept. — Lakewood, Ca, CA 2023 annual report | 0.16–8.19 ug/L | 0.8× the limit |
| Bend, OR 2025 annual report | 8 ug/L | 0.8× the limit |
| Goodyear, AZ 2024 annual report | 8 ug/L | 0.8× the limit |
| Kinneloa Irrigation Dist. — Pasadena, Ca, CA 2021 annual report | 0–8 ug/L | 0.8× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2021 annual report | 8 ug/L | 0.8× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2020 annual report | 8 ug/L | 0.8× the limit |
| North Trails Mutual Water Company — Agua Dulce, Ca, CA 2022 annual report | 8 ug/L | 0.8× the limit |
| Planada Csd — Planada, Ca, CA 2023 annual report | 2.1–8 ug/L | 0.8× the limit |
Within the federal limit (727)
Showing 50 of 727. The full list is in the JSON API.
Frequently asked
+What is Arsenic?
A naturally occurring element that also enters water from industry and agriculture. A known human carcinogen; long-term exposure is linked to skin, bladder, and lung cancer.
+What is the federal limit for Arsenic in drinking water?
The federal MCLG for Arsenic is 10 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 Arsenic over the federal limit?
28 of the 787 public water systems on The Water Map report Arsenic at or above its federal limit, spanning 34 U.S. states. The full list is on this page.
+How can I check if Arsenic 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 Arsenic.