We analyzed tap water quality data for hundreds of cities across the United States to identify those with the highest levels of arsenic. This ranking is based on 2026 data from the EPA and EWG databases.
Arsenic is a contaminant of growing concern in drinking water. The cities below have the highest detected levels based on the most recent testing data available.
Rankings at a Glance
Grand Blanc, Michigan
Grand Blanc has arsenic detected at 35.70 ppb. 10 total contaminants were found in the water supply.
Seagraves, Texas
Seagraves has arsenic detected at 34.90 ppb. 12 total contaminants were found in the water supply.
Bone Gap, Illinois
Bone Gap has arsenic detected at 28.10 ppb. 14 total contaminants were found in the water supply.
Little Diomede, Alaska
Little Diomede has arsenic detected at 26 ppb. 11 total contaminants were found in the water supply.
Ludlow, California
Ludlow has arsenic detected at 25.70 ppb. 8 total contaminants were found in the water supply.
Wellman, Texas
Wellman has arsenic detected at 24.80 ppb. 13 total contaminants were found in the water supply.
Grimes, California
Grimes has arsenic detected at 24.70 ppb. 3 total contaminants were found in the water supply.
Kinde, Michigan
Kinde has arsenic detected at 24.30 ppb. 8 total contaminants were found in the water supply.
Lapeer, Michigan
Lapeer has arsenic detected at 23.80 ppb. 5 total contaminants were found in the water supply.
New Cuyama, California
New Cuyama has arsenic detected at 22.80 ppb. 11 total contaminants were found in the water supply.
Alcalde, New Mexico
Alcalde has arsenic detected at 22 ppb. 11 total contaminants were found in the water supply.
Wolf Creek, Montana
Wolf Creek has arsenic detected at 21.50 ppb. 4 total contaminants were found in the water supply.
Welch, Texas
Welch has arsenic detected at 20.90 ppb. 12 total contaminants were found in the water supply.
Prairie Hill, Texas
Prairie Hill has arsenic detected at 20.80 ppb. 16 total contaminants were found in the water supply.
Auberry, California
Auberry has arsenic detected at 20.30 ppb. 14 total contaminants were found in the water supply.
St. Helens, Oregon
St. Helens has arsenic detected at 20.10 ppb. 1 total contaminants were found in the water supply.
King Hill, Idaho
King Hill has arsenic detected at 19.50 ppb. 4 total contaminants were found in the water supply.
Morris, Minnesota
Morris has arsenic detected at 19.40 ppb. 5 total contaminants were found in the water supply.
Yellowstone National Park, Wyoming
Yellowstone National Park has arsenic detected at 19.30 ppb. 16 total contaminants were found in the water supply.
La Quinta, California
La Quinta has arsenic detected at 19.20 ppb. 2 total contaminants were found in the water supply.
New Home, Texas
New Home has arsenic detected at 19 ppb. 11 total contaminants were found in the water supply.
Nicasio, California
Nicasio has arsenic detected at 18.50 ppb. 15 total contaminants were found in the water supply.
Sunland Park, New Mexico
Sunland Park has arsenic detected at 18.30 ppb. 18 total contaminants were found in the water supply.
Prunedale, California
Prunedale has arsenic detected at 18.10 ppb. 23 total contaminants were found in the water supply.
Freer, Texas
Freer has arsenic detected at 18.10 ppb. 12 total contaminants were found in the water supply.
What We Found: Key Patterns
The most frequently detected contaminants exceeding health guidelines across these cities are Arsenic, Haloacetic acids (HAA5), Total trihalomethanes (TTHMs). These appear repeatedly across different water systems and regions.
Geographically, the states most represented in this ranking are California (7), Texas (6), Michigan (3). Regional water sources, industrial activity, and agricultural runoff all contribute to local water quality variation.
Across all ranked cities, 182 contaminant readings exceed EWG health guidelines, but only 32 exceed EPA legal limits. This gap of 150 highlights how legal standards may not fully protect public health — EPA limits haven't been updated for many contaminants in decades.
Full Rankings Table
| Rank | City | State | Detected | Above Guidelines | Above Legal | People Served |
|---|---|---|---|---|---|---|
| 1 | Grand Blanc | MI | 10 | 6 | 1 | 21,000 |
| 2 | Seagraves | TX | 12 | 9 | 2 | 0 |
| 3 | Bone Gap | IL | 14 | 11 | 1 | 0 |
| 4 | Little Diomede | AK | 11 | 10 | 2 | 0 |
| 5 | Ludlow | CA | 8 | 5 | 2 | 500 |
| 6 | Wellman | TX | 13 | 10 | 2 | 200 |
| 7 | Grimes | CA | 3 | 2 | 1 | 305 |
| 8 | Kinde | MI | 8 | 4 | 1 | 0 |
| 9 | Lapeer | MI | 5 | 4 | 1 | 8,841 |
| 10 | New Cuyama | CA | 11 | 8 | 1 | 700 |
| 11 | Alcalde | NM | 11 | 8 | 1 | 927 |
| 12 | Wolf Creek | MT | 4 | 3 | 1 | 67 |
| 13 | Welch | TX | 12 | 8 | 2 | 315 |
| 14 | Prairie Hill | TX | 16 | 9 | 1 | 2,145 |
| 15 | Auberry | CA | 14 | 10 | 1 | 40 |
| 16 | St. Helens | OR | 1 | 1 | 1 | 2,500 |
| 17 | King Hill | ID | 4 | 3 | 1 | 87 |
| 18 | Morris | MN | 5 | 2 | 1 | 32 |
| 19 | Yellowstone National Park | WY | 16 | 12 | 1 | 7,675 |
| 20 | La Quinta | CA | 2 | 2 | 1 | 340 |
| 21 | New Home | TX | 11 | 9 | 2 | 326 |
| 22 | Nicasio | CA | 15 | 11 | 1 | 31 |
| 23 | Sunland Park | NM | 18 | 12 | 1 | 19,466 |
| 24 | Prunedale | CA | 23 | 16 | 2 | 108 |
| 25 | Freer | TX | 12 | 7 | 1 | 0 |
Frequently Asked Questions
What cities have the highest levels of arsenic?
Our analysis of 2026 data identified the cities with the highest detected levels of arsenic. See the full ranking above.
Is arsenic dangerous in drinking water?
Arsenic has known health risks at elevated levels. The EWG sets health guidelines that are often stricter than EPA legal limits to account for the latest research on long-term exposure.
How do I remove arsenic from my water?
Reverse osmosis (RO) systems are the most effective at removing a wide range of contaminants. Check the specific contaminant details for recommended filtration technology.
What is the EPA legal limit for arsenic?
EPA legal limits vary by contaminant and may differ from EWG health guidelines. See individual city reports for specific legal limit comparisons.
Related Reports
Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)
Last updated: September 2026
Methodology: Contaminant levels are compared against both EPA legal limits (Maximum Contaminant Levels) and EWG health guidelines, which are often stricter and based on the latest scientific research.
