| COLLEGEVILLE TRAPPE JOINT PWD | | 8,470 | 0.2350 ug/L |
| EMMAUS BOROUGH PUBLIC WATER | | 14,000 | 0.1530 ug/L |
| PA AMERICAN AUDUBON | | 8,200 | 0.0579 ug/L |
| CAERNARVON TWP AUTH | | 4,245 | 0.0558 ug/L |
| PALMERTON MUNICIPAL AUTHORITY | | 7,000 | 0.0425 ug/L |
| HORSHAM WATER&SEWER AUTHORITY | | 26,000 | 0.0338 ug/L |
| CITY OF LANCASTER | | 120,000 | 0.0238 ug/L |
| NORTHAMPTON BUCKS CO MUN AUTH | | 36,750 | 0.0230 ug/L |
| VEOLIA WATER BETHEL | | 7,809 | 0.0223 ug/L |
| BUCKINGHAM TWP COLD SPRING | | 4,760 | 0.0220 ug/L |
| AQUA PA HATBORO | | 12,901 | 0.0215 ug/L |
| AQUA PA CHALFONT | | 5,900 | 0.0190 ug/L |
| CORAOPOLIS WATER & SEWER AUTH | | 5,804 | 0.0188 ug/L |
| KENNETT SQUARE MUN WATER WORKS | | 6,328 | 0.0177 ug/L |
| PERKASIE REGIONAL AUTHORITY | | 15,000 | 0.0176 ug/L |
| ASHLAND AREA WATER AUTHORITY | | 4,200 | 0.0170 ug/L |
| N MIDDLETON WATER AUTH | | 8,455 | 0.0169 ug/L |
| PAW PENN DISTRICT | | 28,508 | 0.0164 ug/L |
| UPPER SOUTHAMPTON MUN AUTH | | 16,000 | 0.0164 ug/L |
| AMBLER BORO WATER DEPT | | 20,000 | 0.0153 ug/L |
| TELFORD BOROUGH AUTHORITY | | 7,700 | 0.0152 ug/L |
| EAST PETERSBURG BOROUGH | | 6,215 | 0.0152 ug/L |
| PA AMER WATER CO FRACKVILLE | | 5,583 | 0.0150 ug/L |
| DOYLESTOWN BORO WATER DEPT | | 8,700 | 0.0146 ug/L |
| QUAKERTOWN BORO | | 12,800 | 0.0143 ug/L |
| DTMA MAIN SYSTEM | | 8,655 | 0.0142 ug/L |
| GETTYSBURG MUNI AUTH | | 12,425 | 0.0141 ug/L |
| NORTH WALES WATER AUTHORITY | | 72,496 | 0.0130 ug/L |
| LITTLESTOWN BORO | | 7,300 | 0.0129 ug/L |
| MANHEIM AREA WATER & SEWER AUT | | 6,701 | 0.0128 ug/L |
| PAW GLEN ALSACE DIV | | 24,951 | 0.0127 ug/L |
| VEOLIA MIDDLETOWN | | 9,600 | 0.0127 ug/L |
| AQUA PA MAIN SYSTEM | | 822,600 | 0.0126 ug/L |
| NEWTOWN ARTESIAN WATER CO | | 38,500 | 0.0123 ug/L |
| MONTOURSVILLE WATER COMPANY | | 4,983 | 0.0121 ug/L |
| AQUA PA SUPERIOR MAIN SYSTEM | | 11,400 | 0.0118 ug/L |
| MUHLENBERG TWP MUNI AUTH | | 22,400 | 0.0115 ug/L |
| VEOLIA MECHANICSBURG | | 45,013 | 0.0114 ug/L |
| CARLISLE WATER TRMT PLT | | 26,000 | 0.0113 ug/L |
| SHREWSBURY BOROUGH | | 4,727 | 0.0112 ug/L |
| AQUA PA PERKIOMEN TOWNSHIP | | 3,600 | 0.0108 ug/L |
| PA AMERICAN ROYERSFORD | | 49,508 | 0.0107 ug/L |
| PA AMERICAN WATER CO WEST | | 105,127 | 0.0104 ug/L |
| MOON TWP MUNI AUTH | | 38,000 | 0.0100 ug/L |
| VEOLIA NEWBERRY SYSTEM | | 6,480 | 0.0100 ug/L |
| MILLERSBURG WATER AUTH | | 4,600 | 0.0100 ug/L |
| PA AMERICAN WATER CO YARDLEY | | 33,171 | 0.0097 ug/L |
| DOVER TWP WATER SYS | | 21,097 | 0.0096 ug/L |
| AQUA PA FRIENDSHIP | | 8,800 | 0.0095 ug/L |
| UPPER LEACOCK TOWNSHIP | | 7,734 | 0.0095 ug/L |
| AQUA PA UWCHLAN | | 35,518 | 0.0093 ug/L |
| FREELAND BORO MUNI WATER AUTH | | 4,610 | 0.0091 ug/L |
| NEW HOLLAND BOROUGH | | 8,490 | 0.0083 ug/L |
| RICHLAND TWP WATER AUTHORITY | | 6,800 | 0.0083 ug/L |
| SCHWENKSVILLE BOROUGH AUTH | | 5,200 | 0.0083 ug/L |
| PHILADELPHIA WATER DEPARTMENT | | 1,600,000 | 0.0081 ug/L |
| AQUA PA BENSALEM | | 59,001 | 0.0080 ug/L |
| HILLTOWN TWP WATER&SEWER AUTH | | 5,770 | 0.0080 ug/L |
| PA AMERICAN WATER BERWICK | | 15,282 | 0.0079 ug/L |
| VEOLIA WATER PA DALLAS | | 7,563 | 0.0079 ug/L |
| EAST HEMPFIELD WATER AUTH | | 20,988 | 0.0077 ug/L |
| PA AMER WATER CO LAKE SCRANTON | | 137,142 | 0.0076 ug/L |
| WARWICK TWP WATER & SEWER AUTH | | 14,699 | 0.0076 ug/L |
| PLUMSTEAD NORTHERN SYSTEM | | 2,605 | 0.0075 ug/L |
| BCWSA MAIN LOWER SOUTH | | 52,621 | 0.0073 ug/L |
| BEAVER BORO MUNI AUTH | | 5,799 | 0.0070 ug/L |
| AQUA PA SPRING RUN | | 8,151 | 0.0068 ug/L |
| READING AREA WATER AUTHORITY | | 95,100 | 0.0066 ug/L |
| TUNKHANNOCK BORO MUNIC AUTH | | 5,349 | 0.0066 ug/L |
| AQUA PA FLYING HILLS WA SYS | | 5,100 | 0.0064 ug/L |
| WEST MANCHESTER TWP AUTH | | 9,960 | 0.0062 ug/L |
| UPPER HANOVER WATER AUTHORITY | | 4,600 | 0.0062 ug/L |
| AQUA PA WEST CHESTER | | 48,600 | 0.0059 ug/L |
| PHOENIXVILLE WATER DEPT | | 16,599 | 0.0059 ug/L |
| EEI MEADOWS COMPLEX | | 628 | 0.0059 ug/L |
| EPHRATA AREA JOINT AUTHORITY | | 24,500 | 0.0058 ug/L |
| ELIZABETHTOWN AREA WATER | | 19,000 | 0.0057 ug/L |
| PAWC POCONO DISTRICT | | 17,860 | 0.0057 ug/L |
| MT PENN BORO MUNI AUTH | | 10,400 | 0.0057 ug/L |
| TITUSVILLE MUNICIPAL WATER | | 6,146 | 0.0057 ug/L |
| BEAVER FALLS MUNI AUTH | | 49,500 | 0.0054 ug/L |
| WHITEHALL TWP AUTHORITY | | 13,063 | 0.0054 ug/L |
| MILLERSVILLE UNIV | | 7,950 | 0.0054 ug/L |
| STATE CORRECTIONAL INST | | 3,500 | 0.0053 ug/L |
| WESTERN ALLEGHENY COUNTY MUN A | | 19,031 | 0.0052 ug/L |
| CHESTER WATER AUTHORITY | | 140,437 | 0.0051 ug/L |
| NORTH PENN WATER AUTHORITY | | 91,941 | 0.0051 ug/L |
| WILLIAMSPORT MUN WATER AUTH | | 51,000 | 0.0051 ug/L |
| STATE CORR INST BENNER TWP | | 2,850 | 0.0051 ug/L |
| AKRON BOROUGH | | 4,200 | 0.0050 ug/L |
| EAST COCALICO TOWNSHIP AUTH | | 6,735 | 0.0049 ug/L |
| DILLSBURG AREA AUTHORITY | | 8,962 | 0.0048 ug/L |
| NEW OXFORD MUNCI AUTH | | 3,963 | 0.0048 ug/L |
| MASONIC HOMES | | 3,707 | 0.0048 ug/L |
| WYOMISSING BORO WATER SYSTEM | | 8,500 | 0.0047 ug/L |
| STEWARTSTOWN BORO WATER AUTH | | 5,206 | 0.0046 ug/L |
| AQUA PA BRISTOL | | 28,727 | 0.0045 ug/L |
| HIGHRIDGE WATER AUTH | | 16,000 | 0.0045 ug/L |
| SALISBURY TWP WATER SYSTEM | | 8,522 | 0.0045 ug/L |
| LCA ALLENTOWN DIVISION | | 118,000 | 0.0044 ug/L |