| PHILADELPHIA WATER DEPARTMENT | | 1,600,000 | 0.0148 mg/L |
| AQUA PA MAIN SYSTEM | | 822,600 | 0.0105 mg/L |
| PA AMER WATER CO-PITTSBURGH | | 686,000 | 0.0040 mg/L |
| PITTSBURGH WATER & SEWER AUTH | | 520,000 | 0.0192 mg/L |
| ERIE CITY WATER AUTHORITY | | 220,001 | 0.0056 mg/L |
| YORK WATER CO | | 206,762 | 0.0127 mg/L |
| WEST VIEW WATER AUTHORITY | | 200,000 | 0.0113 mg/L |
| MAWC SWEENEY PLANT | | 143,000 | 0.0101 mg/L |
| CHESTER WATER AUTHORITY | | 140,437 | 0.0123 mg/L |
| PA AMER WATER CO LAKE SCRANTON | | 137,142 | 0.0081 mg/L |
| MAWC YOUGH PLANT | | 133,000 | 0.0054 mg/L |
| WILKINSBURG-PENN JT WATER AUTH | | 125,000 | 0.0128 mg/L |
| CITY OF LANCASTER | | 120,000 | 0.0214 mg/L |
| LCA ALLENTOWN DIVISION | | 118,000 | 0.0106 mg/L |
| CITY OF BETHLEHEM | | 117,259 | 0.0118 mg/L |
| VEOLIA WATER | | 110,000 | 0.0130 mg/L |
| PA AMERICAN WATER CO WEST | | 105,127 | 0.0040 mg/L |
| EASTON AREA WATER SYSTEM | | 96,867 | 0.0077 mg/L |
| READING AREA WATER AUTHORITY | | 95,100 | 0.0105 mg/L |
| NORTH PENN WATER AUTHORITY | | 91,941 | 0.0052 mg/L |
| PA AMERICAN NORRISTOWN | | 88,885 | 0.0064 mg/L |
| NORTH WALES WATER AUTHORITY | | 72,496 | 0.0107 mg/L |
| STATE COLLEGE BORO WATER AUTH | | 72,000 | 0.0119 mg/L |
| CAPITAL REGION WATER | | 66,540 | 0.0095 mg/L |
| LOWER BUCKS CO JOINT MUN AUTH | | 63,007 | 0.0263 mg/L |
| ALTOONA WATER AUTHORITY | | 62,500 | 0.0072 mg/L |
| HAMPTON SHALER WATER AUTHORITY | | 61,949 | 0.0021 mg/L |
| AQUA PA BENSALEM | | 59,001 | 0.0108 mg/L |
| PAW CEASETOWN | | 58,467 | 0.0084 mg/L |
| LEBANON WATER AUTH | | 57,000 | 0.0070 mg/L |
| PAW NESBITT | | 52,640 | 0.0048 mg/L |
| BCWSA MAIN LOWER SOUTH | | 52,621 | 0.0031 mg/L |
| PAW WATRES | | 52,002 | 0.0558 mg/L |
| WILLIAMSPORT MUN WATER AUTH | | 51,000 | 0.0096 mg/L |
| PA AMER WATER CO | | 50,200 | 0.0064 mg/L |
| PA AMERICAN ROYERSFORD | | 49,508 | 0.0070 mg/L |
| BEAVER FALLS MUNI AUTH | | 49,500 | 0.0031 mg/L |
| GREATER JOHNSTOWN WA RIVERSIDE | | 49,500 | 0.0055 mg/L |
| AQUA PA WEST CHESTER | | 48,600 | 0.0062 mg/L |
| MONROEVILLE MUNICIPAL AUTH | | 48,500 | 0.0114 mg/L |
| AQUA PA SHENANGO VALLEY WTP | | 48,000 | 0.0092 mg/L |
| NEW KENSINGTON MUNI AUTH | | 47,800 | 0.0061 mg/L |
| LCA WLSA CENTRAL DIVISION | | 47,693 | 0.0094 mg/L |
| VEOLIA MECHANICSBURG | | 45,013 | 0.0124 mg/L |
| HCA HAZLETON DIVISION | | 45,000 | 0.0212 mg/L |
| PA AMERICAN WATER CO BUTLER | | 43,286 | 0.0060 mg/L |
| PA AMER WATER CO NEW CASTLE | | 43,279 | 0.0040 mg/L |
| AQUA PA ROARING CREEK DIVISION | | 43,000 | 0.0067 mg/L |
| CRANBERRY TWP WTP | | 42,000 | 0.0078 mg/L |
| HANOVER MUNI WATER WORKS | | 40,900 | 0.0136 mg/L |
| SOUTHWESTERN PA WATER AUTH | | 40,200 | 0.0050 mg/L |
| NORTHAMPTON BORO MUNI AUTH | | 40,000 | 0.0040 mg/L |
| OAKMONT WATER AUTHORITY | | 39,901 | 0.0091 mg/L |
| NEWTOWN ARTESIAN WATER CO | | 38,500 | 0.0169 mg/L |
| MOON TWP MUNI AUTH | | 38,000 | 0.0049 mg/L |
| PENN STATE UNIV | | 37,000 | 0.0132 mg/L |
| PA AMERICAN COATESVILLE | | 36,960 | 0.0100 mg/L |
| NORTHAMPTON BUCKS CO MUN AUTH | | 36,750 | 0.0094 mg/L |
| POTTSTOWN BOROUGH WATER AUTH | | 36,000 | 0.0067 mg/L |
| WARMINSTER MUNICIPAL AUTHORITY | | 36,000 | 0.0088 mg/L |
| AQUA PA UWCHLAN | | 35,518 | 0.0064 mg/L |
| NORTH FAYETTE CNTY MUNI AUTH | | 35,409 | 0.0117 mg/L |
| PA AMERICAN WATER CO YARDLEY | | 33,171 | 0.0054 mg/L |
| WEST CNTY MUNI AUTH-MCKEESPORT | | 32,644 | 0.0077 mg/L |
| SCHUYLKILL CO MUN AUTH | | 31,850 | 0.0242 mg/L |
| CHAMBERSBURG BORO WATER SYS | | 31,048 | 0.0085 mg/L |
| PA AMERICAN WHITE DEER | | 30,209 | 0.0028 mg/L |
| BRODHEAD CREEK REG WATER AUTH | | 30,000 | 0.0040 mg/L |
| LATROBE MUNI AUTH | | 30,000 | 0.0116 mg/L |
| MIFFLIN CNTY MUNI AUTH | | 29,432 | 0.0028 mg/L |
| VEOLIA WATER PA INC BLOOMSBURG | | 29,382 | 0.0098 mg/L |
| AQUA PA BRISTOL | | 28,727 | 0.0154 mg/L |
| PAW PENN DISTRICT | | 28,508 | 0.0086 mg/L |
| GUILFORD WATER AUTH | | 28,135 | 0.0019 mg/L |
| PLUM BORO MUNI AUTH | | 27,500 | 0.0073 mg/L |
| AUTH OF BORO OF CHARLEROI | | 27,000 | 0.0056 mg/L |
| CARLISLE WATER TRMT PLT | | 26,000 | 0.0105 mg/L |
| HORSHAM WATER&SEWER AUTHORITY | | 26,000 | 0.0065 mg/L |
| COLUMBIA WATER CO | | 25,200 | 0.0231 mg/L |
| PAW GLEN ALSACE DIV | | 24,951 | 0.0050 mg/L |
| EPHRATA AREA JOINT AUTHORITY | | 24,500 | 0.0044 mg/L |
| FALLS TWP WATER & SEWER DEPT | | 24,400 | 0.0077 mg/L |
| PAW BLUE MOUNTAIN DIVISION | | 23,763 | 0.0060 mg/L |
| PA-AMERICAN WATER- UNIONTOWN | | 23,125 | 0.0136 mg/L |
| HIGHLAND S & W AUTH BEAVERDAM | | 22,617 | 0.0125 mg/L |
| MUHLENBERG TWP MUNI AUTH | | 22,400 | 0.0057 mg/L |
| PA AMERICAN WATER CO-INDIANA D | | 22,360 | 0.0064 mg/L |
| NWWA WARRINGTON TOWNSHIP | | 21,588 | 0.0049 mg/L |
| DOVER TWP WATER SYS | | 21,097 | 0.0182 mg/L |
| EAST HEMPFIELD WATER AUTH | | 20,988 | 0.0117 mg/L |
| PAW PHILIPSBURG | | 20,865 | 0.0020 mg/L |
| AMBLER BORO WATER DEPT | | 20,000 | 0.0098 mg/L |
| ST MARYS AREA WATER AUTH | | 19,588 | 0.0118 mg/L |
| AMBRIDGE WATER AUTH | | 19,500 | 0.0156 mg/L |
| WESTERN ALLEGHENY COUNTY MUN A | | 19,031 | 0.0060 mg/L |
| ELIZABETHTOWN AREA WATER | | 19,000 | 0.0050 mg/L |
| CENTER TWP WATER AUTH | | 19,000 | 0.0096 mg/L |
| FOX CHAPEL AUTH | | 18,500 | 0.0108 mg/L |
| BRADFORD CITY WATER AUTHORITY | | 18,500 | 0.0106 mg/L |
| PAWC POCONO DISTRICT | | 17,860 | 0.0116 mg/L |