| ERIE CITY WATER AUTHORITY | 220,001 | 408 | Clean |
| SUMMIT TOWNSHIP WATER AUTHORIT | 12,500 | 633 | Clean |
| MUNICIPAL AUTHORITY OF CORRY | 7,800 | 383 | Clean |
| EDINBORO WATER AUTHORITY | 7,800 | 428 | Clean |
| NORTH EAST TOWNSHIP WATER | 5,848 | 314 | — |
| ALBION BOROUGH | 5,842 | 214 | Clean |
| NORTH EAST BOROUGH WATER DEPT | 4,601 | 407 | Clean |
| FAIRVIEW TWP WATER DISTRICT 1 | 4,500 | 90 | Clean |
| FAIRVIEW TWP WATER AUTH DIST 3 | 3,320 | 158 | Clean |
| GIRARD BORO WATER DEPT | 3,301 | 1,016 | Clean |
| UNION CITY MUNICIPAL AUTHORITY | 2,952 | 629 | Clean |
| LAKE CITY BORO MUNIC WATER | 2,935 | 318 | — |
| GENERAL MCLANE SCHOOLS | 2,000 | 191 | — |
| WATTSBURG AREA SCHOOL COMPLEX | 1,900 | 327 | — |
| WATERFORD MUNICIPAL AUTHORITY | 1,700 | 429 | Clean |
| IMPERIAL POINT WATER SERVICE | 1,500 | 432 | — |
| MCKEAN TWP WATERWORKS | 1,048 | 22 | — |
| LAKESHORE WATER ASSN | 800 | 273 | — |
| FAMILY AFFAIR CAMPGROUND | 800 | 140 | — |
| WASHINGTON TWP WATER SYSTEM | 797 | 18 | Clean |
| CRANESVILLE WATER DEPARTMENT | 638 | 83 | — |
| PORT FARMS | 600 | 53 | — |
| WATTSBURG BORO WTP | 450 | 279 | — |
| CAMPERS HILL | 400 | 35 | — |
| MILLFAIR HEIGHTS WATER SYSTEM | 390 | 169 | — |
| HICKORY HILL COUNTRY VILLAGE | 375 | 266 | — |
| WOODHAVEN MOBILE HOME PARK | 350 | 775 | — |
| HOLLY ACRES MHP | 315 | 316 | — |
| RAINBOW VALLEY MOBILE HOME | 300 | 168 | — |
| MOUNT PLEASANT OF EDINBORO | 300 | 35 | — |
| HAWTHORNE RIDGE CAMP | 300 | 69 | — |
| API TECHNOLOGIES MFG | 300 | 300 | — |
| CAMP ERIEZ | 300 | 105 | — |
| PHB DIE CASTING | 264 | 55 | — |
| EAST SPRINGFIELD ELEM SCHOOL | 240 | 153 | — |
| PA DOT REST AREA L | 201 | 16 | — |
| PHB MACHINING DIVISION | 200 | 105 | — |
| CAMP SHERWIN | 200 | 100 | — |
| SPARROW POND CAMP GROUND | 200 | 48 | — |
| YOUNGSTOWN YMCA CAMP FITCH BR | 196 | 508 | — |
| COUNTRY GARDENS TRAILER COURT | 180 | 198 | — |
| PEACEFUL ACRES TRAILERS | 165 | 145 | — |
| PALMER SHORE WATER | 150 | 533 | — |
| GRANNYS FREEZER | 150 | 73 | — |
| EDINBORO CONFERENCE GROUNDS | 150 | 122 | — |
| THE SCOOP | 150 | 65 | — |
| FED EX ERIE FACILITY | 150 | 395 | — |
| MILLVILLAGE ELEMENTARY SCHOOL | 135 | 48 | — |
| WEST HAVEN RV PARK & ESTATES | 120 | 53 | — |
| MAJESTIC HEIGHTS | 110 | 192 | — |