| AQUA PA MAIN SYSTEM | 822,600 | 453 | Detected |
| NORTH PENN WATER AUTHORITY | 91,941 | 209 | Detected |
| PA AMERICAN NORRISTOWN | 88,885 | 92 | Detected |
| NORTH WALES WATER AUTHORITY | 72,496 | 422 | Detected |
| POTTSTOWN BOROUGH WATER AUTH | 36,000 | 172 | Detected |
| HORSHAM WATER&SEWER AUTHORITY | 26,000 | 572 | Detected |
| AMBLER BORO WATER DEPT | 20,000 | 2,896 | Detected |
| AQUA PA HATBORO | 12,901 | 402 | Detected |
| AQUA PA SUPERIOR MAIN SYSTEM | 11,400 | 1,406 | Detected |
| MERCK AND CO INC | 8,550 | 70 | Detected |
| COLLEGEVILLE TRAPPE JOINT PWD | 8,470 | 434 | Detected |
| PA AMERICAN AUDUBON | 8,200 | 5,456 | Detected |
| TELFORD BOROUGH AUTHORITY | 7,700 | 224 | Detected |
| SCHWENKSVILLE BOROUGH AUTH | 5,200 | 158 | Detected |
| UPPER HANOVER WATER AUTHORITY | 4,600 | 1,170 | Detected |
| AQUA PA PERKIOMEN TOWNSHIP | 3,600 | 136 | Detected |
| RADISSON VALLEY FORGE HOTEL | 3,500 | 685 | Detected |
| E GREENVILLE BORO WATER DEPT | 3,100 | 69 | — |
| RED HILL WATER AUTHORITY | 2,500 | 761 | — |
| VALLEY FORGE NATL PARK | 2,300 | 101 | — |
| HATFIELD QUALITY MEATS INC | 1,850 | 48 | — |
| CONSTELLATION NUCLEAR PWR PLNT | 1,650 | 123 | — |
| UPPER DUBLIN HIGH SCHOOL | 1,473 | 49 | — |
| POTTSTOWN HOSP TOWER HEALTH | 1,425 | 10 | — |
| VILLAGE OF NESHAMINY FALLS | 1,300 | 56 | — |
| PARKHOUSE NURSING & REHAB CTR | 1,200 | 466 | — |
| AQUA PA PERKIOMEN WOODS | 1,100 | 39 | — |
| SPRING MOUNTAIN ADVENTURES | 1,000 | 11 | — |
| NEW HANOVER UPPER FRED E S | 850 | 138 | — |
| AQUA PA UPPER PROVIDENCE | 810 | 0 | — |
| GILBERTSVILLE ELEMENTARY | 800 | 134 | — |
| MARLBOROUGH ELEMENTARY SCHOOL | 800 | 126 | — |
| JEFFERSON HOSPITAL LANSDALE | 700 | 25 | — |
| FREDERICK LIVING | 640 | 241 | — |
| CAMP HART MUSSER RESERVATION | 600 | 76 | — |
| FORT WASHINGTON ELEM SCHOOL | 532 | 20 | — |
| PERKIOMEN CROSSING | 508 | 66 | — |
| AQUA PA SUPERIOR CENTER POINT | 500 | 644 | — |
| SALFORD HILLS ELEM SCHOOL | 500 | 486 | — |
| HICKORY VALLEY G C SNACK BAR | 500 | 7 | — |
| HORSHAM CLINIC | 488 | 94 | — |
| BIDDLE AIR NATIONAL GUARD BASE | 440 | 178 | — |
| CAMP HOPE FOR KIDS | 410 | 99 | — |
| LIMERICK DINER | 400 | 97 | — |
| INDIAN VALLEY COUNTRY CLUB | 400 | 45 | — |
| FLOURTOWN SWIM CLUB | 350 | 118 | — |
| CAMP GREEN LANE | 350 | 104 | — |
| LEHIGH VALLEY DAIRIES NTNC | 328 | 67 | — |
| GREEN HILL MHP | 323 | 296 | — |
| AVANTE APARTMENTS | 315 | 392 | — |