We analyzed tap water quality data for hundreds of cities across the United States to identify the 25 with the most contaminants exceeding health guidelines. This ranking is based on 2026 data from the EPA and EWG databases.
While all public water systems must meet EPA legal limits, many health experts — including the Environmental Working Group — argue that these legal limits are outdated and don't reflect current scientific understanding of safe exposure levels. The cities below have the widest gap between what's in their water and what's considered safe by modern health standards.
Rankings at a Glance
Hialeah Gardens, Florida
Hialeah Gardens has 28 contaminants exceeding EWG health guidelines out of 59 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Hialeah Gardens water report →Corona, California
Corona has 25 contaminants exceeding EWG health guidelines out of 46 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Corona water report →Camden, New Jersey
Camden has 24 contaminants exceeding EWG health guidelines out of 48 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Camden water report →Livingston, New Jersey
Livingston has 24 contaminants exceeding EWG health guidelines out of 48 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Livingston water report →Marshfield, Wisconsin
Marshfield has 24 contaminants exceeding EWG health guidelines out of 39 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Marshfield water report →Coupland, Texas
Coupland has 23 contaminants exceeding EWG health guidelines out of 50 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Coupland water report →Ramsey, New Jersey
Ramsey has 23 contaminants exceeding EWG health guidelines out of 46 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Ramsey water report →Pleasanton, California
Pleasanton has 23 contaminants exceeding EWG health guidelines out of 43 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Pleasanton water report →Fresno, California
Fresno has 22 contaminants exceeding EWG health guidelines out of 51 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Fresno water report →Moorestown, New Jersey
Moorestown has 22 contaminants exceeding EWG health guidelines out of 48 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Moorestown water report →Anaheim, California
Anaheim has 22 contaminants exceeding EWG health guidelines out of 44 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Anaheim water report →East Hanover Township, New Jersey
East Hanover Township has 22 contaminants exceeding EWG health guidelines out of 44 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full East Hanover Township water report →Lake Elsinore, California
Lake Elsinore has 22 contaminants exceeding EWG health guidelines out of 42 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Lake Elsinore water report →Wildomar, California
Wildomar has 22 contaminants exceeding EWG health guidelines out of 42 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Wildomar water report →Maple Shade, New Jersey
Maple Shade has 22 contaminants exceeding EWG health guidelines out of 39 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Maple Shade water report →Wilmington, North Carolina
Wilmington has 22 contaminants exceeding EWG health guidelines out of 37 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Wilmington water report →Thornton, Colorado
Thornton has 22 contaminants exceeding EWG health guidelines out of 37 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Thornton water report →Compton, California
Compton has 22 contaminants exceeding EWG health guidelines out of 35 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Compton water report →Perry, New York
Perry has 21 contaminants exceeding EWG health guidelines out of 77 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Perry water report →Galena Park, Texas
Galena Park has 21 contaminants exceeding EWG health guidelines out of 55 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Galena Park water report →Hudson, Massachusetts
Hudson has 21 contaminants exceeding EWG health guidelines out of 46 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Hudson water report →Fort Drum, New York
Fort Drum has 21 contaminants exceeding EWG health guidelines out of 45 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Fort Drum water report →Norwalk, California
Norwalk has 21 contaminants exceeding EWG health guidelines out of 45 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Norwalk water report →Essex Falls, New Jersey
Essex Falls has 21 contaminants exceeding EWG health guidelines out of 45 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Essex Falls water report →Woodbury, New Jersey
Woodbury has 21 contaminants exceeding EWG health guidelines out of 44 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Woodbury water report →What We Found: Key Patterns
The most frequently detected contaminants exceeding health guidelines across these cities are Bromodichloromethane, Chloroform, Dibromochloromethane. These appear repeatedly across different water systems and regions.
Geographically, the states most represented in this ranking are California (8), New Jersey (8), Texas (2). Regional water sources, industrial activity, and agricultural runoff all contribute to local water quality variation.
Across all ranked cities, 561 contaminant readings exceed EWG health guidelines, but only 21 exceed EPA legal limits. This gap of 540 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 | Hialeah Gardens | FL | 59 | 28 | 2 | 22,200 |
| 2 | Corona | CA | 46 | 25 | 2 | 168,751 |
| 3 | Camden | NJ | 48 | 24 | 2 | 46,585 |
| 4 | Livingston | NJ | 48 | 24 | 1 | 27,391 |
| 5 | Marshfield | WI | 39 | 24 | 1 | 18,708 |
| 6 | Coupland | TX | 50 | 23 | 0 | 39,648 |
| 7 | Ramsey | NJ | 46 | 23 | 1 | 15,207 |
| 8 | Pleasanton | CA | 43 | 23 | 2 | 79,871 |
| 9 | Fresno | CA | 51 | 22 | 0 | 545,466 |
| 10 | Moorestown | NJ | 48 | 22 | 0 | 20,700 |
| 11 | Anaheim | CA | 44 | 22 | 2 | 341,245 |
| 12 | East Hanover Township | NJ | 44 | 22 | 2 | 11,393 |
| 13 | Lake Elsinore | CA | 42 | 22 | 1 | 165,586 |
| 14 | Wildomar | CA | 42 | 22 | 0 | 4,026 |
| 15 | Maple Shade | NJ | 39 | 22 | 0 | 19,400 |
| 16 | Wilmington | NC | 37 | 22 | 1 | 180,516 |
| 17 | Thornton | CO | 37 | 22 | 0 | 155,700 |
| 18 | Compton | CA | 35 | 22 | 0 | 74,877 |
| 19 | Perry | NY | 77 | 21 | 0 | 4,348 |
| 20 | Galena Park | TX | 55 | 21 | 0 | 10,293 |
| 21 | Hudson | MA | 46 | 21 | 1 | 18,406 |
| 22 | Fort Drum | NY | 45 | 21 | 0 | 34,400 |
| 23 | Norwalk | CA | 45 | 21 | 1 | 17,790 |
| 24 | Essex Falls | NJ | 45 | 21 | 2 | 2,200 |
| 25 | Woodbury | NJ | 44 | 21 | 0 | 9,963 |
Frequently Asked Questions
What city has the worst tap water in the US?
Based on 2026 data, Hialeah Gardens, FL has the most contaminants exceeding EWG health guidelines among the cities we analyzed.
How are cities ranked in this report?
Cities are ranked by the number of contaminants exceeding EWG health guidelines. These guidelines are typically stricter than EPA legal limits and reflect current scientific research on safe exposure levels.
Is my tap water safe if my city isn't on this list?
Not necessarily. Even cities not on this list may have contaminants of concern. We recommend checking your specific water quality using our free water scan tool.
What's the best water filter for contaminated water?
A reverse osmosis (RO) system is the most effective for removing the widest range of contaminants. For whole-home protection, a combination of RO for drinking water and a whole-home filter for showers and baths is recommended.
Related Reports
Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)
Last updated: April 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.
