We analyzed tap water quality data for hundreds of cities across the United States to identify those with the highest levels of 1,4-dioxane. This ranking is based on 2026 data from the EPA and EWG databases.
1,4-Dioxane 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
Sanford, North Carolina
Sanford has 1,4-dioxane detected at 5.83 ppb. 30 total contaminants were found in the water supply.
Broadway, North Carolina
Broadway has 1,4-dioxane detected at 5.83 ppb. 30 total contaminants were found in the water supply.
Goldston, North Carolina
Goldston has 1,4-dioxane detected at 5.83 ppb. 30 total contaminants were found in the water supply.
New Brighton, Minnesota
New Brighton has 1,4-dioxane detected at 4.20 ppb. 21 total contaminants were found in the water supply.
Maywood, California
Maywood has 1,4-dioxane detected at 4.10 ppb. 28 total contaminants were found in the water supply.
Cudahy, California
Cudahy has 1,4-dioxane detected at 3.71 ppb. 29 total contaminants were found in the water supply.
Lillington, North Carolina
Lillington has 1,4-dioxane detected at 3.55 ppb. 35 total contaminants were found in the water supply.
Angier, North Carolina
Angier has 1,4-dioxane detected at 3.55 ppb. 35 total contaminants were found in the water supply.
Coats, North Carolina
Coats has 1,4-dioxane detected at 3.55 ppb. 35 total contaminants were found in the water supply.
Linden, North Carolina
Linden has 1,4-dioxane detected at 3.55 ppb. 35 total contaminants were found in the water supply.
Holly Springs, North Carolina
Holly Springs has 1,4-dioxane detected at 3.28 ppb. 35 total contaminants were found in the water supply.
Fort Liberty, North Carolina
Fort Liberty has 1,4-dioxane detected at 3.20 ppb. 26 total contaminants were found in the water supply.
Dunn, North Carolina
Dunn has 1,4-dioxane detected at 2.95 ppb. 30 total contaminants were found in the water supply.
Falcon, North Carolina
Falcon has 1,4-dioxane detected at 2.95 ppb. 30 total contaminants were found in the water supply.
Hempstead, New York
Hempstead has 1,4-dioxane detected at 2.81 ppb. 22 total contaminants were found in the water supply.
Camden, New Jersey
Camden has 1,4-dioxane detected at 2.70 ppb. 48 total contaminants were found in the water supply.
Beaver Falls, Pennsylvania
Beaver Falls has 1,4-dioxane detected at 2.66 ppb. 29 total contaminants were found in the water supply.
Zelienople, Pennsylvania
Zelienople has 1,4-dioxane detected at 2.66 ppb. 29 total contaminants were found in the water supply.
Conway, Pennsylvania
Conway has 1,4-dioxane detected at 2.66 ppb. 29 total contaminants were found in the water supply.
Wilmington, North Carolina
Wilmington has 1,4-dioxane detected at 2.38 ppb. 37 total contaminants were found in the water supply.
Burgaw, North Carolina
Burgaw has 1,4-dioxane detected at 2.21 ppb. 31 total contaminants were found in the water supply.
Leland, North Carolina
Leland has 1,4-dioxane detected at 2.21 ppb. 19 total contaminants were found in the water supply.
Bellflower, California
Bellflower has 1,4-dioxane detected at 2.06 ppb. 29 total contaminants were found in the water supply.
Cherry Hill, New Jersey
Cherry Hill has 1,4-dioxane detected at 1.95 ppb. 31 total contaminants were found in the water supply.
Pennsauken, New Jersey
Pennsauken has 1,4-dioxane detected at 1.94 ppb. 45 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 Dibromoacetic acid, Dibromochloromethane, Haloacetic acids (HAA5). These appear repeatedly across different water systems and regions.
Geographically, the states most represented in this ranking are North Carolina (14), California (3), New Jersey (3). Regional water sources, industrial activity, and agricultural runoff all contribute to local water quality variation.
Across all ranked cities, 428 contaminant readings exceed EWG health guidelines, but only 28 exceed EPA legal limits. This gap of 400 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 | Sanford | NC | 30 | 15 | 2 | 47,302 |
| 2 | Broadway | NC | 30 | 15 | 2 | 1,783 |
| 3 | Goldston | NC | 30 | 15 | 2 | 1,285 |
| 4 | New Brighton | MN | 21 | 12 | 0 | 22,902 |
| 5 | Maywood | CA | 28 | 18 | 1 | 9,500 |
| 6 | Cudahy | CA | 29 | 17 | 2 | 14,000 |
| 7 | Lillington | NC | 35 | 21 | 1 | 109,415 |
| 8 | Angier | NC | 35 | 21 | 2 | 8,468 |
| 9 | Coats | NC | 35 | 21 | 1 | 2,831 |
| 10 | Linden | NC | 35 | 21 | 1 | 2,077 |
| 11 | Holly Springs | NC | 35 | 21 | 2 | 45,058 |
| 12 | Fort Liberty | NC | 26 | 16 | 2 | 65,000 |
| 13 | Dunn | NC | 30 | 17 | 2 | 12,088 |
| 14 | Falcon | NC | 30 | 17 | 2 | 714 |
| 15 | Hempstead | NY | 22 | 10 | 0 | 56,000 |
| 16 | Camden | NJ | 48 | 24 | 2 | 46,585 |
| 17 | Beaver Falls | PA | 29 | 14 | 0 | 50,000 |
| 18 | Zelienople | PA | 29 | 14 | 0 | 4,123 |
| 19 | Conway | PA | 29 | 14 | 0 | 2,176 |
| 20 | Wilmington | NC | 37 | 22 | 1 | 180,516 |
| 21 | Burgaw | NC | 31 | 17 | 0 | 30,506 |
| 22 | Leland | NC | 19 | 12 | 0 | 45,748 |
| 23 | Bellflower | CA | 29 | 16 | 1 | 46,300 |
| 24 | Cherry Hill | NJ | 31 | 18 | 0 | 10,719 |
| 25 | Pennsauken | NJ | 45 | 20 | 2 | 47,144 |
Frequently Asked Questions
What cities have the highest levels of 1,4-dioxane?
Our analysis of 2026 data identified the cities with the highest detected levels of 1,4-dioxane. See the full ranking above.
Is 1,4-dioxane dangerous in drinking water?
1,4-Dioxane 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 1,4-dioxane 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 1,4-dioxane?
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.
