We analyzed tap water quality data for hundreds of cities in Rhode Island 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EPA legal limits, many health experts — including the Environmental Working Group — argue that these legal limits are outdated and don't reflect current scientific understanding of safe exposure levels.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
Newport, Rhode Island
Newport has 21 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 Newport water report →Portsmouth, Rhode Island
Portsmouth has 20 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 Portsmouth water report →Cumberland, Rhode Island
Cumberland has 18 contaminants exceeding EWG health guidelines out of 36 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Cumberland water report →West Warwick, Rhode Island
West Warwick has 17 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 West Warwick water report →Rumford, Rhode Island
Rumford has 17 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 Rumford water report →Pawtucket, Rhode Island
Pawtucket has 17 contaminants exceeding EWG health guidelines out of 30 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Pawtucket water report →Westerly, Rhode Island
Westerly has 17 contaminants exceeding EWG health guidelines out of 27 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Westerly water report →Exeter, Rhode Island
Exeter has 16 contaminants exceeding EWG health guidelines out of 23 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Exeter water report →Woonsocket, Rhode Island
Woonsocket has 14 contaminants exceeding EWG health guidelines out of 31 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Woonsocket water report →North Smithfield, Rhode Island
North Smithfield has 14 contaminants exceeding EWG health guidelines out of 31 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full North Smithfield water report →Pascoag, Rhode Island
Pascoag has 14 contaminants exceeding EWG health guidelines out of 28 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Pascoag water report →Harrisville, Rhode Island
Harrisville has 14 contaminants exceeding EWG health guidelines out of 21 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Harrisville water report →Jamestown, Rhode Island
Jamestown has 14 contaminants exceeding EWG health guidelines out of 18 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Jamestown water report →North Kingstown, Rhode Island
North Kingstown has 13 contaminants exceeding EWG health guidelines out of 33 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full North Kingstown water report →Kingston, Rhode Island
Kingston has 13 contaminants exceeding EWG health guidelines out of 26 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Kingston water report →Narragansett, Rhode Island
Narragansett has 13 contaminants exceeding EWG health guidelines out of 21 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Narragansett water report →Wakefield, Rhode Island
Wakefield has 13 contaminants exceeding EWG health guidelines out of 20 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Wakefield water report →Slatersville, Rhode Island
Slatersville has 13 contaminants exceeding EWG health guidelines out of 20 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Slatersville water report →Lincoln, Rhode Island
Lincoln has 10 contaminants exceeding EWG health guidelines out of 20 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Lincoln water report →Bristol, Rhode Island
Bristol has 10 contaminants exceeding EWG health guidelines out of 18 detected — significantly above the national average. Multiple known carcinogens were found at levels of concern.
See full Bristol water report →Warren, Rhode Island
Warren has 9 contaminants exceeding EWG health guidelines out of 21 total detected, placing it among the most concerning water supplies analyzed.
See full Warren water report →Warwick, Rhode Island
Warwick has 9 contaminants exceeding EWG health guidelines out of 20 total detected, placing it among the most concerning water supplies analyzed.
See full Warwick water report →East Providence, Rhode Island
East Providence has 9 contaminants exceeding EWG health guidelines out of 20 total detected, placing it among the most concerning water supplies analyzed.
See full East Providence water report →Greenville, Rhode Island
Greenville has 9 contaminants exceeding EWG health guidelines out of 19 total detected, placing it among the most concerning water supplies analyzed.
See full Greenville water report →Smithfield, Rhode Island
Smithfield has 9 contaminants exceeding EWG health guidelines out of 19 total detected, placing it among the most concerning water supplies analyzed.
See full Smithfield water report →What We Found: Key Patterns
The most frequently detected contaminants exceeding health guidelines across these cities are Dibromochloromethane, Total trihalomethanes (TTHMs), Bromodichloromethane. These appear repeatedly across different water systems and regions.
Water quality varies significantly even within the same state, driven by local geology, agricultural activity, and industrial proximity.
Across all ranked cities, 343 contaminant readings exceed EWG health guidelines, but only 6 exceed EPA legal limits. This gap of 337 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 | Newport | RI | 42 | 21 | 0 | 42,155 |
| 2 | Portsmouth | RI | 42 | 20 | 0 | 17,090 |
| 3 | Cumberland | RI | 36 | 18 | 0 | 21,235 |
| 4 | West Warwick | RI | 39 | 17 | 0 | 88,779 |
| 5 | Rumford | RI | 39 | 17 | 0 | 9,999 |
| 6 | Pawtucket | RI | 30 | 17 | 1 | 98,130 |
| 7 | Westerly | RI | 27 | 17 | 0 | 35,298 |
| 8 | Exeter | RI | 23 | 16 | 3 | 300 |
| 9 | Woonsocket | RI | 31 | 14 | 0 | 45,869 |
| 10 | North Smithfield | RI | 31 | 14 | 0 | 0 |
| 11 | Pascoag | RI | 28 | 14 | 0 | 2,985 |
| 12 | Harrisville | RI | 21 | 14 | 0 | 3,012 |
| 13 | Jamestown | RI | 18 | 14 | 0 | 3,294 |
| 14 | North Kingstown | RI | 33 | 13 | 0 | 25,200 |
| 15 | Kingston | RI | 26 | 13 | 2 | 19,354 |
| 16 | Narragansett | RI | 21 | 13 | 0 | 8,210 |
| 17 | Wakefield | RI | 20 | 13 | 0 | 22,347 |
| 18 | Slatersville | RI | 20 | 13 | 0 | 750 |
| 19 | Lincoln | RI | 20 | 10 | 0 | 21,664 |
| 20 | Bristol | RI | 18 | 10 | 0 | 0 |
| 21 | Warren | RI | 21 | 9 | 0 | 49,000 |
| 22 | Warwick | RI | 20 | 9 | 0 | 73,289 |
| 23 | East Providence | RI | 20 | 9 | 0 | 47,618 |
| 24 | Greenville | RI | 19 | 9 | 0 | 9,500 |
| 25 | Smithfield | RI | 19 | 9 | 0 | 9,460 |
Frequently Asked Questions
What city has the worst tap water in Rhode Island?
Based on 2026 data, Newport, RI 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.
