Pennsylvania drinking water quality
Pennsylvania has 7,658 active public water systems serving 12.6 million people. 4,800 of them, 63%, had at least one EPA violation in the past three years, 1,399 have an unresolved violation today, and 148 are designated serious violators by the EPA.
Active systems
7,658
in 67 counties
People served
12.6M
1,849 community systems serve 11.5M
Violations, past 3 years
4,800
63% of active systems
Serious violators
148
278 systems carry a health flag
Largest counties
All 67 counties| County | People served | Systems | With violations |
|---|---|---|---|
| Allegheny | 2,017,752 | 70 | 48 |
| Philadelphia | 1,601,175 | 6 | 6 |
| Montgomery | 1,273,934 | 167 | 102 |
| Bucks | 595,902 | 304 | 187 |
| Lancaster | 409,262 | 427 | 220 |
| York | 390,174 | 209 | 115 |
| Berks | 383,012 | 490 | 240 |
| Northampton | 334,319 | 204 | 85 |
| Luzerne | 324,521 | 247 | 167 |
| Erie | 305,434 | 145 | 110 |
Largest community water systems
All 7,658 systems| System | Serves | Status |
|---|---|---|
| Philadelphia Water Department Philadelphia County |
1,600,000 | |
| Aqua PA Main System Montgomery County |
822,600 | |
| PA Amer Water Co-Pittsburgh Allegheny County |
686,000 | |
| Pittsburgh Water & Sewer Auth Allegheny County |
520,000 | |
| Erie City Water Authority Erie County |
220,001 | |
| York Water CO York County |
206,762 | |
| West View Water Authority Allegheny County |
200,000 | |
| Mawc Sweeney Plant Westmoreland County |
143,000 | |
| Chester Water Authority Delaware County |
140,437 | |
| PA Amer Water CO Lake Scranton Lackawanna County |
137,142 |
About the Pennsylvania data
Retrieved from EPA ECHO on Oct 11, 2026. EPA records for Pennsylvania systems do not include town names, so searches here match on ZIP code, street address, or county.