Water Quality in Pennsylvania
1,855 water systems • 733 cities • EPA SDWIS Data
1,855
Water Systems
199,265
Total Violations
6,042
Health-Based Violations
11,468,960
Population Served
Overview
Pennsylvania has 1,855 active community water systems serving 11,468,960 people. These systems have accumulated 199,265 EPA Safe Drinking Water Act violations on record, of which 6,042 are health-based violations (meaning a contaminant exceeded safe levels).
Common contaminants found in violations: Chlorine Dioxide, Barium, Disinfection Byproducts, Total Haloacetic Acids (HAA5), E. coli, Fecal Coliform, TTHM, cis-1,2-Dichloroethylene, Ethylene Dibromide, 1,2-Dichloroethane.
Cities with Most Violations in Pennsylvania
| # | City | Violations | Health-Based | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Moscow | 10,318 | 54 | 16 | 2,311 |
| 2 | Norristown | 5,674 | 3 | 8 | 99,147 |
| 3 | Lake Ariel | 3,048 | 61 | 7 | 6,852 |
| 4 | Morgantown | 2,264 | 121 | 45 | 14,065 |
| 5 | Tunkhannock | 2,255 | 29 | 8 | 6,458 |
| 6 | Durham | 2,251 | 31 | 14 | 1,730 |
| 7 | Effort | 2,004 | 9 | 2 | 279 |
| 8 | Spring Mills | 1,820 | 16 | 4 | 834 |
| 9 | Bedford | 1,443 | 106 | 6 | 7,163 |
| 10 | East Greenville | 1,421 | 2 | 4 | 10,275 |
Largest Cities in Pennsylvania
| # | City | Population | Violations | Water Systems |
|---|---|---|---|---|
| 1 | Philadelphia | 1,600,000 | 11 | 1 |
| 2 | Bryn Mawr | 1,057,337 | 480 | 25 |
| 3 | Pittsburgh | 801,168 | 612 | 13 |
| 4 | Mcmurray | 686,000 | 5 | 1 |
| 5 | Greensburg | 311,784 | 176 | 5 |
| 6 | Harrisburg | 248,203 | 489 | 15 |
| 7 | Erie | 234,255 | 889 | 8 |
| 8 | York | 222,980 | 387 | 13 |
| 9 | Allentown | 198,541 | 403 | 18 |
| 10 | Scranton | 187,283 | 18 | 12 |
All Cities in Pennsylvania
| City | Population | Violations | Health Violations | Contaminants |
|---|---|---|---|---|
| Philadelphia | 1,600,000 | 11 | 0 | |
| Bryn Mawr | 1,057,337 | 480 | 7 | Chlorine Dioxide, E. coli |
| Pittsburgh | 801,168 | 612 | 89 | Disinfection Byproducts, E. coli, Fecal Coliform |
| Mcmurray | 686,000 | 5 | 1 | E. coli |
| Greensburg | 311,784 | 176 | 12 | Contaminant 2920, E. coli, Fecal Coliform +2 more |
| Harrisburg | 248,203 | 489 | 11 | Barium, Chlorine Dioxide, Disinfection Byproducts +2 more |
| Erie | 234,255 | 889 | 12 | E. coli, TTHM |
| York | 222,980 | 387 | 28 | Barium, Chlorine Dioxide, E. coli +1 more |
| Allentown | 198,541 | 403 | 6 | Chlorine Dioxide, E. coli, Endrin +1 more |
| Scranton | 187,283 | 18 | 0 | |
| Reading | 174,731 | 377 | 16 | Bromate, E. coli, Fecal Coliform |
| New Castle | 162,213 | 510 | 6 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Wilkes Barre | 159,289 | 0 | 0 | |
| Chester | 140,437 | 0 | 0 | |
| Mechanicsburg | 132,536 | 419 | 1 | Chlorine Dioxide |
| Wilkinsburg | 125,000 | 41 | 1 | TTHM |
| Bethlehem | 124,424 | 1,231 | 9 | Chlorine Dioxide, E. coli, Selenium |
| Lancaster | 121,292 | 357 | 38 | Chlorine Dioxide, Disinfection Byproducts, E. coli +4 more |
| Norristown | 99,147 | 5,674 | 3 | Chlorine Dioxide |
| North Wales | 97,309 | 375 | 4 | Disinfection Byproducts, Fecal Coliform |
| Easton | 97,259 | 350 | 24 | Chlorine Dioxide, Copper, Disinfection Byproducts |
| Lansdale | 92,162 | 256 | 16 | Chlorine Dioxide |
| Johnstown | 81,025 | 712 | 149 | Contaminant 2920, TTHM, Total Haloacetic Acids (HAA5) |
| State College | 78,220 | 207 | 2 | Chlorine Dioxide |
| Sharon | 64,159 | 105 | 62 | Chlorine Dioxide, TTHM, Total Haloacetic Acids (HAA5) |
| Levittown | 63,007 | 38 | 0 | |
| Altoona | 62,795 | 135 | 4 | Contaminant 1085, E. coli, Fecal Coliform |
| Allison Park | 61,949 | 20 | 0 | |
| Lebanon | 61,603 | 216 | 4 | Chlorine Dioxide |
| Warrington | 60,188 | 1,129 | 22 | Chlorine Dioxide, E. coli, Fecal Coliform +2 more |
| Chambersburg | 59,934 | 388 | 4 | Chlorine Dioxide, E. coli, Lead |
| Shamokin | 57,240 | 154 | 4 | Chlorine Dioxide, Gross Alpha, Total Haloacetic Acids (HAA5) |
| Hummelstown | 56,628 | 48 | 23 | E. coli, TTHM, Total Haloacetic Acids (HAA5) |
| Milton | 55,347 | 382 | 25 | Barium, Chlorine Dioxide |
| Beaver Falls | 54,078 | 84 | 0 | |
| East Stroudsburg | 52,340 | 892 | 63 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Williamsport | 51,788 | 942 | 12 | Chlorine Dioxide, E. coli |
| Spring City | 49,508 | 10 | 2 | E. coli |
| Monroeville | 48,500 | 6 | 6 | TTHM, Total Haloacetic Acids (HAA5) |
| New Kensington | 47,800 | 0 | 0 | |
| Hazleton | 47,708 | 210 | 2 | Chlorine Dioxide |
| Cranberry Twp | 42,400 | 25 | 2 | Chlorine Dioxide |
| Northampton | 41,345 | 127 | 15 | Chlorine Dioxide, Disinfection Byproducts, Selenium |
| Hanover | 40,900 | 31 | 2 | Contaminant 2920, Fecal Coliform |
| Newtown | 40,515 | 351 | 12 | Barium, Chlorine Dioxide, Disinfection Byproducts |
| Carlisle | 40,392 | 929 | 14 | Chlorine Dioxide, Contaminant 2920, Disinfection Byproducts +1 more |
| Coatesville | 40,386 | 358 | 15 | Chlorine Dioxide, Disinfection Byproducts, Selenium |
| Warminster | 40,000 | 15 | 0 | |
| Jefferson | 40,000 | 36 | 2 | TTHM |
| Pottstown | 39,971 | 374 | 21 | Bromate, Chlorine Dioxide, Fecal Coliform |
| Oakmont | 39,901 | 18 | 0 | |
| Moon Township | 38,000 | 9 | 2 | TTHM |
| University Park | 37,000 | 145 | 0 | |
| Richboro | 36,750 | 460 | 4 | E. coli, Fecal Coliform |
| Pottsville | 36,085 | 109 | 3 | E. coli |
| White Haven | 36,032 | 587 | 13 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Dunbar | 35,409 | 49 | 0 | |
| Aliquippa | 34,685 | 191 | 4 | Bromate, Chlorine Dioxide, E. coli +1 more |
| Uniontown | 34,550 | 7 | 0 | |
| Clarks Summit | 33,518 | 73 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Yardley | 33,171 | 7 | 1 | E. coli |
| Bloomsburg | 30,271 | 81 | 6 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Latrobe | 30,000 | 56 | 4 | E. coli |
| Columbia | 29,286 | 437 | 8 | Chlorine Dioxide, Contaminant 2920, Disinfection Byproducts |
| Charleroi | 27,000 | 96 | 12 | E. coli, TTHM |
| Milroy | 26,825 | 57 | 0 | |
| Horsham | 26,000 | 356 | 2 | Chlorine Dioxide |
| Ephrata | 25,028 | 44 | 2 | Selenium |
| Philipsburg | 24,783 | 55 | 0 | |
| Fairless Hills | 24,444 | 171 | 5 | Chlorine Dioxide, Total Haloacetic Acids (HAA5) |
| Elizabethtown | 24,379 | 683 | 29 | Chlorine Dioxide, Disinfection Byproducts, Selenium +1 more |
| Dover | 23,552 | 171 | 24 | Chlorine Dioxide, HAA5 |
| Bushkill | 22,623 | 290 | 9 | Chlorine Dioxide, Disinfection Byproducts |
| Lititz | 22,085 | 427 | 25 | Chlorine Dioxide, E. coli, Fecal Coliform +1 more |
| Tobyhanna | 21,832 | 371 | 7 | Chlorine Dioxide |
| Waynesboro | 21,394 | 681 | 0 | |
| Sellersville | 21,070 | 799 | 0 | |
| Landisville | 20,988 | 31 | 1 | Selenium |
| Oakdale | 20,915 | 48 | 2 | E. coli |
| Quakertown | 20,350 | 153 | 0 | |
| Blairsville | 20,113 | 415 | 18 | Contaminant 2920, E. coli, Endrin +2 more |
| Ambler | 20,040 | 1,047 | 0 | |
| Meadville | 19,833 | 624 | 5 | E. coli |
| Ambridge | 19,703 | 140 | 13 | Chlorine Dioxide, Contaminant 2920, E. coli |
| Saint Marys | 19,588 | 53 | 1 | Total Haloacetic Acids (HAA5) |
| Bellefonte | 19,004 | 751 | 6 | Chlorine Dioxide, E. coli |
| Bradford | 18,500 | 41 | 5 | Chlorine Dioxide, TTHM |
| Shippensburg | 18,297 | 107 | 5 | Total Haloacetic Acids (HAA5) |
| Natrona Heights | 18,061 | 34 | 13 | TTHM |
| Doylestown | 17,655 | 125 | 0 | |
| Phoenixville | 16,599 | 149 | 2 | Contaminant 2920 |
| Warren | 16,491 | 339 | 4 | Chlorine Dioxide |
| Gettysburg | 16,451 | 339 | 0 | |
| Southampton | 16,000 | 82 | 7 | E. coli, Fecal Coliform |
| Huntingdon | 15,976 | 76 | 0 | |
| Slippery Rock | 15,915 | 399 | 2 | Disinfection Byproducts, Gross Alpha |
| Kutztown | 15,887 | 173 | 4 | Chlorine Dioxide |
| Red Lion | 15,882 | 151 | 0 | |
| Sayre | 15,607 | 117 | 2 | Gross Alpha |
| Mount Joy | 15,261 | 8 | 0 | |
| Belle Vernon | 15,100 | 200 | 9 | Chlorine Dioxide, Contaminant 2920, E. coli +2 more |
| South Heights | 15,000 | 6 | 1 | Disinfection Byproducts |
| Jamison | 14,699 | 17 | 0 | |
| Indiana | 14,693 | 693 | 272 | Chlorine Dioxide, Contaminant 2920, TTHM +1 more |
| Morgantown | 14,065 | 2,264 | 121 | Chlorine Dioxide, Disinfection Byproducts, E. coli +6 more |
| Emmaus | 14,000 | 106 | 3 | E. coli |
| Clearfield | 14,000 | 49 | 3 | E. coli, Fecal Coliform |
| Beaver | 13,719 | 177 | 0 | |
| Morrisville | 13,342 | 251 | 21 | E. coli, Total Haloacetic Acids (HAA5) |
| Honesdale | 13,149 | 1,142 | 33 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Whitehall | 13,063 | 2 | 0 | |
| Somerset | 12,750 | 549 | 11 | Chlorine Dioxide, Disinfection Byproducts, Fecal Coliform |
| Grove City | 12,691 | 99 | 0 | |
| St Thomas | 12,589 | 54 | 1 | Fecal Coliform |
| Franklin | 12,584 | 114 | 3 | Chlorine Dioxide |
| Downingtown | 12,568 | 72 | 0 | |
| Dallastown | 12,300 | 43 | 0 | |
| Greenville | 11,970 | 144 | 17 | Contaminant 2920, E. coli, TTHM +1 more |
| Dubois | 11,837 | 923 | 2 | Chlorine Dioxide |
| Boiling Springs | 11,695 | 83 | 2 | Chlorine Dioxide |
| Clinton | 11,460 | 48 | 0 | |
| Oil City | 11,443 | 10 | 0 | |
| Fairview | 11,063 | 746 | 16 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Sunbury | 11,043 | 192 | 3 | E. coli |
| Mill Hall | 10,686 | 904 | 37 | Chlorine Dioxide, E. coli, Fecal Coliform +1 more |
| North East | 10,669 | 399 | 49 | Chlorine Dioxide, Contaminant 2920, Disinfection Byproducts +1 more |
| Mars | 10,656 | 127 | 1 | E. coli |
| Denver | 10,596 | 109 | 5 | 1,2-Dichloroethane, Fecal Coliform |
| Lehighton | 10,481 | 478 | 26 | Chlorine Dioxide, Disinfection Byproducts |
| Manheim | 10,340 | 101 | 3 | Fecal Coliform, Gross Alpha |
| East Greenville | 10,275 | 1,421 | 2 | Chlorine Dioxide, Disinfection Byproducts |
| Gibsonia | 10,190 | 4 | 0 | |
| Fredericktown | 10,100 | 245 | 88 | Carbofuran, Chlorine Dioxide, Contaminant 2920 +2 more |
| Lock Haven | 10,025 | 133 | 4 | E. coli, Gross Alpha |
| Myerstown | 9,934 | 93 | 0 | |
| Ford City | 9,735 | 45 | 3 | Chlorine Dioxide |
| Middletown | 9,676 | 76 | 0 | |
| Windber | 9,463 | 46 | 0 | |
| Newmanstown | 9,440 | 71 | 0 | |
| Center Valley | 9,429 | 189 | 0 | |
| Buckingham | 9,315 | 315 | 0 | |
| Lansford | 9,300 | 24 | 4 | Chlorine Dioxide, Fecal Coliform |
| Sewickley | 9,000 | 21 | 1 | E. coli |
| Lords Valley | 8,821 | 226 | 15 | Chlorine Dioxide, E. coli |
| Edinboro | 8,757 | 193 | 0 | |
| Ebensburg | 8,581 | 255 | 65 | Chlorine Dioxide, TTHM, Total Haloacetic Acids (HAA5) |
| Hollidaysburg | 8,558 | 39 | 3 | Chlorine Dioxide |
| Dillsburg | 8,506 | 8 | 1 | Chlorine Dioxide |
| Wyomissing | 8,500 | 6 | 0 | |
| Trappe | 8,470 | 16 | 2 | Chlorine Dioxide |
| Wellsboro | 8,445 | 471 | 6 | Bromate, Chlorine Dioxide, E. coli |
| Houtzdale | 8,410 | 28 | 4 | E. coli |
| Boyertown | 8,000 | 12 | 1 | Contaminant 2920 |
| Tamaqua | 8,000 | 92 | 21 | Fecal Coliform, Total Haloacetic Acids (HAA5) |
| Adrian | 8,000 | 162 | 0 | |
| Millersville | 7,950 | 43 | 3 | Chlorine Dioxide, Gross Alpha |
| Tyrone | 7,910 | 1,091 | 1 | Chlorine Dioxide |
| Corry | 7,877 | 89 | 2 | Chlorine Dioxide |
| Mcmurry | 7,844 | 5 | 0 | |
| Davidsville | 7,800 | 270 | 0 | |
| Leola | 7,782 | 87 | 4 | Chlorine Dioxide, TTHM |
| Leetsdale | 7,781 | 6 | 2 | TTHM |
| West Grove | 7,763 | 118 | 7 | Chlorine Dioxide |
| Telford | 7,700 | 75 | 0 | |
| Wernersville | 7,654 | 12 | 0 | |
| Littlestown | 7,570 | 375 | 1 | Chlorine Dioxide |
| Blandon | 7,505 | 4 | 0 | |
| Selinsgrove | 7,366 | 814 | 6 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Minersville | 7,275 | 93 | 0 | |
| Jersey Shore | 7,200 | 795 | 8 | Chlorine Dioxide, Contaminant 2920, E. coli +1 more |
| Bedford | 7,163 | 1,443 | 106 | Bromate, Chlorine Dioxide, Contaminant 2920 +3 more |
| Mansfield | 7,100 | 509 | 11 | Chlorine Dioxide, Contaminant 2920, E. coli +2 more |
| New Philadelphia | 7,100 | 27 | 0 | |
| Montoursville | 7,024 | 519 | 19 | Chlorine Dioxide, Disinfection Byproducts, Lead +1 more |
| Palmerton | 7,000 | 161 | 1 | Chlorine Dioxide |
| Indian Head | 7,000 | 308 | 0 | |
| Kennett Square | 6,888 | 585 | 10 | Chlorine Dioxide |
| Towanda | 6,886 | 328 | 8 | Chlorine Dioxide, Fecal Coliform |
| Lake Ariel | 6,852 | 3,048 | 61 | Barium, Chlorine Dioxide, Disinfection Byproducts +2 more |
| Greencastle | 6,785 | 175 | 9 | E. coli, Selenium |
| Mcadoo | 6,700 | 52 | 2 | Disinfection Byproducts |
| Harmony | 6,669 | 41 | 12 | Fecal Coliform, TTHM |
| Catasauqua | 6,598 | 22 | 0 | |
| Ridgway | 6,563 | 70 | 7 | E. coli, TTHM, Total Haloacetic Acids (HAA5) |
| Portage | 6,500 | 706 | 5 | Chlorine Dioxide, Contaminant 2920 |
| Monaca | 6,500 | 139 | 6 | Chlorine Dioxide, E. coli |
| Derry | 6,500 | 66 | 0 | |
| Cresson | 6,460 | 202 | 0 | |
| Tunkhannock | 6,458 | 2,255 | 29 | Chlorine Dioxide, E. coli |
| Pipersville | 6,332 | 554 | 4 | Chlorine Dioxide, HAA5 |
| Brookville | 6,220 | 23 | 0 | |
| East Petersburg | 6,215 | 12 | 2 | Fecal Coliform |
| Titusville | 6,181 | 44 | 7 | Chlorine Dioxide |
| Sarver | 6,031 | 48 | 12 | TTHM |
| Schuylkill Haven | 6,000 | 85 | 0 | |
| Hellertown | 5,950 | 169 | 0 | |
| New Holland | 5,865 | 27 | 0 | |
| Albion | 5,842 | 128 | 4 | Chlorine Dioxide |
| Coraopolis | 5,804 | 8 | 0 | |
| Mount Union | 5,801 | 218 | 6 | Fecal Coliform, TTHM |
| Muncy | 5,760 | 939 | 7 | Chlorine Dioxide, E. coli |
| Sharpsville | 5,670 | 48 | 0 | |
| Mahanoy City | 5,584 | 47 | 0 | |
| Duquesne | 5,565 | 62 | 13 | TTHM |
| Birdsboro | 5,453 | 67 | 20 | E. coli, Total Haloacetic Acids (HAA5) |
| Oxford | 5,340 | 58 | 2 | Chlorine Dioxide |
| Stewartstown | 5,260 | 407 | 1 | Disinfection Byproducts |
| Farmington Hills | 5,255 | 171 | 2 | Chlorine Dioxide |
| Hamburg | 5,230 | 52 | 1 | Chlorine Dioxide |
| Schwenksville | 5,200 | 32 | 1 | Barium |
| Seneca | 5,185 | 64 | 0 | |
| Jim Thorpe | 5,127 | 51 | 2 | Contaminant 2920 |
| Cheswick | 5,061 | 20 | 0 | |
| Danville | 4,992 | 303 | 7 | E. coli |
| East Berlin | 4,971 | 82 | 0 | |
| Tarentum | 4,952 | 83 | 2 | TTHM |
| Duncansville | 4,944 | 95 | 1 | Fecal Coliform |
| Homer City | 4,920 | 17 | 0 | |
| Mifflintown | 4,780 | 152 | 17 | Chlorine Dioxide, E. coli |
| Shrewsbury | 4,727 | 316 | 0 | |
| Freeland | 4,722 | 215 | 10 | Chlorine Dioxide |
| Mifflinburg | 4,648 | 306 | 1 | Chlorine Dioxide |
| Industry | 4,615 | 144 | 0 | |
| Millersburg | 4,600 | 89 | 0 | |
| Fleetwood | 4,567 | 165 | 4 | Chlorine Dioxide |
| Northern Cambria | 4,500 | 191 | 0 | |
| Curwensville | 4,500 | 247 | 8 | Total Haloacetic Acids (HAA5) |
| New Wilmington | 4,500 | 12 | 0 | |
| Spinnerstown | 4,497 | 6 | 0 | |
| New Freedom | 4,464 | 71 | 0 | |
| Slatington | 4,450 | 53 | 4 | E. coli |
| Brockway | 4,384 | 527 | 0 | |
| Brownstown | 4,327 | 17 | 3 | Chlorine Dioxide, Total Haloacetic Acids (HAA5) |
| West Reading | 4,300 | 12 | 3 | Fecal Coliform |
| Rochester | 4,276 | 10 | 2 | E. coli |
| Mineral Point | 4,236 | 237 | 108 | Surface Water Treatment, TTHM, Total Haloacetic Acids (HAA5) |
| Walnutport | 4,220 | 459 | 11 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Ashland | 4,200 | 100 | 0 | |
| Dilliner | 4,200 | 252 | 24 | Chlorine Dioxide, Contaminant 2920, E. coli |
| Akron | 4,200 | 17 | 0 | |
| Zelienople | 4,123 | 38 | 1 | E. coli |
| Wrightsville | 4,076 | 26 | 2 | Contaminant 2920, TTHM |
| Nicholson | 4,059 | 152 | 0 | |
| Annville | 4,052 | 486 | 1 | Chlorine Dioxide |
| Dallas | 4,034 | 676 | 1 | Chlorine Dioxide |
| Camp Hill | 4,008 | 373 | 7 | Chlorine Dioxide |
| Quarryville | 3,980 | 282 | 7 | Chlorine Dioxide, Fecal Coliform |
| New Oxford | 3,963 | 25 | 1 | Contaminant 2920 |
| Baden | 3,948 | 31 | 0 | |
| Coudersport | 3,916 | 803 | 3 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Point Marion | 3,900 | 595 | 99 | Bromate, Chlorine Dioxide, Contaminant 2920 +4 more |
| Honey Brook | 3,872 | 316 | 3 | Chlorine Dioxide, Disinfection Byproducts |
| Valley View | 3,870 | 11 | 1 | Chlorine Dioxide |
| Fairchance | 3,856 | 119 | 3 | E. coli |
| Irvona | 3,855 | 181 | 4 | Fecal Coliform, Total Haloacetic Acids (HAA5) |
| Masontown | 3,841 | 41 | 8 | Contaminant 2920, Total Haloacetic Acids (HAA5) |
| Petrolia | 3,800 | 13 | 0 | |
| Brackenridge | 3,700 | 53 | 2 | TTHM |
| Morrisdale | 3,700 | 287 | 2 | Fecal Coliform |
| Ligonier | 3,682 | 380 | 0 | |
| Girard | 3,676 | 128 | 0 | |
| Connellsville | 3,630 | 32 | 15 | Total Haloacetic Acids (HAA5) |
| Martinsburg | 3,625 | 24 | 1 | Chlorine Dioxide |
| Bath | 3,595 | 166 | 7 | Chlorine Dioxide |
| Perkasie | 3,494 | 101 | 0 | |
| Boswell | 3,476 | 77 | 0 | |
| Snow Shoe | 3,456 | 45 | 4 | Chlorine Dioxide, E. coli |
| Auburn | 3,420 | 211 | 5 | Chlorine Dioxide, E. coli |
| Springdale | 3,405 | 1 | 0 | |
| Orwigsburg | 3,380 | 64 | 6 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Roaring Spring | 3,357 | 43 | 0 | |
| Lykens | 3,320 | 129 | 23 | Disinfection Byproducts, Total Haloacetic Acids (HAA5) |
| Emporium | 3,300 | 203 | 5 | Contaminant 2920 |
| East Earl | 3,288 | 49 | 4 | Chlorine Dioxide |
| Mercersburg | 3,262 | 336 | 9 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Mt Holly Springs | 3,261 | 64 | 1 | Chlorine Dioxide |
| Mingoville | 3,250 | 113 | 3 | Chlorine Dioxide |
| Conyngham | 3,230 | 151 | 4 | Chlorine Dioxide |
| Central City | 3,230 | 27 | 0 | |
| Flinton | 3,200 | 24 | 6 | E. coli |
| Newport | 3,200 | 391 | 3 | Disinfection Byproducts |
| Strasburg | 3,180 | 63 | 13 | Selenium, Total Organic Carbon |
| Bellwood | 3,162 | 9 | 0 | |
| Reynoldsville | 3,158 | 125 | 14 | Disinfection Byproducts, TTHM, Total Haloacetic Acids (HAA5) |
| Nanty Glo | 3,152 | 76 | 21 | Chlorine Dioxide, Contaminant 2920, Fecal Coliform +3 more |
| Midland | 3,151 | 928 | 48 | Chlorine Dioxide, Contaminant 2920, Fecal Coliform +1 more |
| Tower City | 3,150 | 100 | 0 | |
| Renovo | 3,150 | 868 | 21 | Bromate, E. coli |
| New Bethlehem | 3,150 | 67 | 16 | Contaminant 2920, TTHM |
| Gallitzin | 3,130 | 122 | 6 | Chlorine Dioxide, Contaminant 2920, E. coli +1 more |
| Milford | 3,128 | 1,010 | 24 | Chlorine Dioxide, Disinfection Byproducts |
| Macungie | 3,107 | 30 | 1 | Chlorine Dioxide |
| Seven Fields | 3,100 | 5 | 0 | |
| Kittanning | 3,060 | 71 | 0 | |
| Champion | 3,000 | 57 | 0 | |
| Lake City | 2,985 | 212 | 4 | E. coli |
| Nesquehoning | 2,975 | 268 | 8 | Chlorine Dioxide, Disinfection Byproducts |
| Union City | 2,952 | 150 | 1 | Total Haloacetic Acids (HAA5) |
| Matamoras | 2,900 | 292 | 3 | E. coli |
| Summit Hill | 2,890 | 20 | 2 | Chlorine Dioxide |
| Claysburg | 2,800 | 120 | 0 | |
| Hughesville | 2,800 | 137 | 2 | Chlorine Dioxide |
| Markleysburg | 2,800 | 122 | 1 | E. coli |
| Everett | 2,798 | 35 | 0 | |
| Cambridge Springs | 2,798 | 108 | 4 | Total Haloacetic Acids (HAA5) |
| Pine Grove | 2,751 | 46 | 2 | Chlorine Dioxide |
| Milesburg | 2,750 | 60 | 3 | Chlorine Dioxide |
| Youngstown | 2,730 | 26 | 0 | |
| Montgomery | 2,700 | 257 | 7 | Chlorine Dioxide |
| Elizabethville | 2,700 | 9 | 0 | |
| Elkland | 2,660 | 546 | 4 | Chlorine Dioxide, E. coli |
| Meyersdale | 2,636 | 160 | 16 | Total Haloacetic Acids (HAA5) |
| Mercer | 2,621 | 525 | 6 | Chlorine Dioxide |
| Biglerville | 2,621 | 5 | 0 | |
| Weatherly | 2,612 | 494 | 1 | Disinfection Byproducts |
| Royersford | 2,608 | 117 | 5 | Chlorine Dioxide |
| Bentleyville | 2,600 | 77 | 5 | TTHM |
| Port Allegany | 2,591 | 19 | 0 | |
| Coopersburg | 2,570 | 53 | 0 | |
| Duncannon | 2,558 | 437 | 19 | Barium, Chlorine Dioxide, Disinfection Byproducts |
| Loretto | 2,552 | 41 | 0 | |
| Dublin | 2,505 | 362 | 0 | |
| Topton | 2,479 | 80 | 2 | Disinfection Byproducts, E. coli |
| Berlin | 2,468 | 19 | 0 | |
| Smethport | 2,456 | 298 | 7 | Chlorine Dioxide, E. coli |
| Reinholds | 2,430 | 15 | 0 | |
| Johnsonburg | 2,413 | 838 | 30 | E. coli, TTHM, Total Haloacetic Acids (HAA5) |
| Williamstown | 2,390 | 61 | 0 | |
| Halifax | 2,353 | 96 | 0 | |
| New Hope | 2,342 | 144 | 0 | |
| Moscow | 2,311 | 10,318 | 54 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Shoemakersville | 2,295 | 19 | 2 | E. coli |
| Leesport | 2,249 | 43 | 1 | Chlorine Dioxide |
| Oley | 2,204 | 73 | 0 | |
| Conway | 2,176 | 19 | 0 | |
| Troy | 2,152 | 555 | 1 | Gross Alpha |
| Fairfield | 2,150 | 47 | 0 | |
| Bally | 2,146 | 74 | 0 | |
| Alburtis | 2,117 | 12 | 0 | |
| Port Matilda | 2,115 | 224 | 0 | |
| Hastings | 2,100 | 52 | 0 | |
| Newville | 2,070 | 65 | 2 | Contaminant 2920 |
| Canton | 2,050 | 65 | 0 | |
| Vandergrift | 2,049 | 23 | 0 | |
| Monsey | 2,000 | 75 | 9 | Chlorine Dioxide |
| Mc Connellsburg | 2,000 | 397 | 0 | |
| Creighton | 2,000 | 23 | 2 | TTHM |
| Glen Rock | 2,000 | 17 | 0 | |
| Evans City | 1,990 | 33 | 0 | |
| Youngsville | 1,957 | 146 | 0 | |
| Beech Creek | 1,940 | 364 | 0 | |
| Centre Hall | 1,900 | 52 | 3 | Disinfection Byproducts |
| Elderton | 1,875 | 56 | 1 | E. coli |
| Rimersburg | 1,873 | 9 | 0 | |
| Farmington | 1,850 | 307 | 4 | E. coli |
| Worthington | 1,823 | 189 | 3 | Chlorine Dioxide, Disinfection Byproducts |
| Patton | 1,805 | 95 | 10 | Chlorine Dioxide, TTHM |
| Williamsburg | 1,800 | 20 | 0 | |
| Adamstown | 1,800 | 7 | 0 | |
| Greentown | 1,773 | 675 | 41 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Glasgow | 1,746 | 37 | 0 | |
| Durham | 1,730 | 2,251 | 31 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Loysburg | 1,724 | 91 | 6 | Chlorine Dioxide |
| Elverson | 1,716 | 76 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Braddock | 1,708 | 16 | 5 | TTHM |
| Mont Alto | 1,705 | 167 | 2 | Chlorine Dioxide |
| Shamokin Dam | 1,700 | 38 | 1 | Contaminant 2920 |
| Clymer | 1,700 | 25 | 1 | Disinfection Byproducts |
| Frenchville | 1,700 | 19 | 0 | |
| Waterford | 1,700 | 184 | 19 | Chlorine Dioxide, E. coli |
| Richland | 1,700 | 3 | 0 | |
| Intercourse | 1,690 | 49 | 1 | Disinfection Byproducts |
| Leechburg | 1,680 | 11 | 0 | |
| Saxton | 1,675 | 207 | 3 | E. coli, Total Haloacetic Acids (HAA5) |
| Linesville | 1,675 | 54 | 1 | Chlorine Dioxide |
| Blossburg | 1,650 | 40 | 0 | |
| Twin Rocks | 1,650 | 67 | 36 | Fecal Coliform, TTHM, Total Haloacetic Acids (HAA5) |
| Catawissa | 1,644 | 46 | 0 | |
| Jennerstown | 1,625 | 27 | 0 | |
| Middleburg | 1,600 | 125 | 1 | E. coli |
| Harwick | 1,600 | 12 | 1 | Disinfection Byproducts |
| Numine | 1,595 | 293 | 4 | Chlorine Dioxide |
| Luthersburg | 1,570 | 388 | 1 | Chlorine Dioxide |
| Lemoyne | 1,500 | 133 | 8 | Chlorine Dioxide, Disinfection Byproducts |
| Mount Morris | 1,500 | 27 | 6 | TTHM |
| Hawthorn | 1,500 | 283 | 20 | Contaminant 2920, Fecal Coliform, Total Haloacetic Acids (HAA5) |
| Saegertown | 1,500 | 165 | 0 | |
| Sykesville | 1,500 | 60 | 5 | E. coli, Fecal Coliform |
| Richlandtown | 1,450 | 111 | 0 | |
| Mc Connellstown | 1,450 | 31 | 0 | |
| Vanport | 1,450 | 47 | 0 | |
| Falls Creek | 1,440 | 146 | 36 | E. coli, Fecal Coliform, TTHM +1 more |
| Howard | 1,431 | 117 | 0 | |
| Cochranton | 1,415 | 223 | 3 | Chlorine Dioxide, Disinfection Byproducts |
| Banner Elk | 1,410 | 378 | 37 | Chlorine Dioxide, Disinfection Byproducts |
| Atglen | 1,406 | 19 | 0 | |
| East Freedom | 1,400 | 2 | 0 | |
| Sipesville | 1,400 | 149 | 0 | |
| Grampian | 1,400 | 12 | 0 | |
| Delta | 1,400 | 22 | 0 | |
| Lilly | 1,388 | 141 | 0 | |
| Knox | 1,380 | 22 | 0 | |
| Benton | 1,373 | 208 | 0 | |
| Windsor | 1,332 | 7 | 0 | |
| Rockwood | 1,325 | 42 | 0 | |
| Westfield | 1,300 | 218 | 3 | Chlorine Dioxide |
| Roulette | 1,300 | 489 | 2 | Disinfection Byproducts |
| Sheffield | 1,300 | 37 | 1 | E. coli |
| Bainbridge | 1,295 | 66 | 0 | |
| Parker | 1,270 | 566 | 149 | Chlorine Dioxide, TTHM, Total Haloacetic Acids (HAA5) |
| Chicora | 1,250 | 66 | 1 | Chlorine Dioxide |
| Ellsworth | 1,250 | 107 | 8 | TTHM |
| Shinglehouse | 1,250 | 187 | 0 | |
| Freeport | 1,230 | 57 | 15 | TTHM |
| West Chester | 1,200 | 95 | 4 | Chlorine Dioxide, Disinfection Byproducts |
| East Bangor | 1,200 | 108 | 1 | Fecal Coliform |
| Orbisonia | 1,200 | 37 | 3 | Chlorine Dioxide |
| Galeton | 1,200 | 216 | 3 | Disinfection Byproducts, Fecal Coliform |
| Arendtsville | 1,200 | 48 | 0 | |
| Fredericksburg | 1,200 | 30 | 2 | Chlorine Dioxide |
| Springboro | 1,175 | 39 | 0 | |
| New Bloomfield | 1,170 | 152 | 0 | |
| Elmora | 1,158 | 368 | 41 | Bromate, Total Haloacetic Acids (HAA5) |
| New Milford | 1,146 | 110 | 2 | Chlorine Dioxide, E. coli |
| Shavertown | 1,144 | 245 | 7 | Chlorine Dioxide, Disinfection Byproducts |
| Weedville | 1,131 | 338 | 10 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Christiana | 1,130 | 51 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Avondale | 1,108 | 53 | 0 | |
| Mill Creek | 1,108 | 101 | 0 | |
| Portland | 1,100 | 86 | 1 | Fecal Coliform |
| Bessemer | 1,100 | 17 | 5 | Chlorine Dioxide |
| Sandy Lake | 1,100 | 32 | 0 | |
| York Springs | 1,095 | 10 | 0 | |
| Stroudsburg | 1,089 | 706 | 40 | Chlorine Dioxide |
| Royalton | 1,083 | 9 | 1 | Disinfection Byproducts |
| Thompsontown | 1,060 | 518 | 5 | E. coli |
| Polk | 1,058 | 183 | 38 | Contaminant 2920, E. coli, TTHM |
| East Brady | 1,040 | 24 | 7 | Chlorine Dioxide |
| Tidioute | 1,040 | 77 | 42 | Total Haloacetic Acids (HAA5) |
| Bendersville | 1,039 | 94 | 0 | |
| Conneaut Lake | 1,035 | 463 | 10 | Chlorine Dioxide, E. coli, Total Haloacetic Acids (HAA5) |
| Mount Gretna | 1,035 | 179 | 2 | Chlorine Dioxide |
| Trumbauersville | 1,034 | 541 | 24 | 1,2-Dichloroethane, Barium, Chlorine Dioxide +3 more |
| Hamlin | 1,024 | 1,290 | 12 | Chlorine Dioxide |
| Bernville | 1,010 | 9 | 0 | |
| Colver | 1,000 | 60 | 1 | Fecal Coliform |
| Pennsylvania Furnace | 1,000 | 520 | 17 | Chlorine Dioxide, E. coli |
| Richfield | 1,000 | 26 | 1 | Disinfection Byproducts |
| Rural Valley | 1,000 | 38 | 2 | Chlorine Dioxide |
| Torrance | 997 | 23 | 0 | |
| New Berlin | 990 | 20 | 0 | |
| Summerhill | 989 | 64 | 2 | Total Haloacetic Acids (HAA5) |
| Riegelsville | 980 | 173 | 2 | Chlorine Dioxide |
| Kreamer | 980 | 28 | 0 | |
| Schaefferstown | 975 | 4 | 0 | |
| Millville | 969 | 469 | 2 | Chlorine Dioxide |
| Beaver Meadows | 968 | 43 | 1 | Fecal Coliform |
| Lahaska | 960 | 62 | 0 | |
| Penfield | 960 | 45 | 0 | |
| Stoneboro | 956 | 39 | 0 | |
| Loganton | 952 | 753 | 7 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Port Royal | 950 | 237 | 0 | |
| Cabot | 950 | 17 | 1 | Chlorine Dioxide |
| South Mountain | 950 | 455 | 1 | Fecal Coliform |
| Beavertown | 935 | 178 | 0 | |
| Liverpool | 934 | 63 | 0 | |
| Foxburg | 925 | 141 | 1 | Chlorine Dioxide |
| Drums | 924 | 315 | 9 | Chlorine Dioxide, Disinfection Byproducts |
| Landisburg | 919 | 917 | 31 | Barium, Chlorine Dioxide, E. coli |
| Hyndman | 910 | 111 | 0 | |
| Cairnbrook | 910 | 67 | 0 | |
| Carrolltown | 905 | 455 | 3 | Chlorine Dioxide |
| Millheim | 902 | 311 | 2 | Chlorine Dioxide |
| Bowmanstown | 900 | 83 | 0 | |
| Distant | 900 | 76 | 7 | TTHM |
| Quentin | 900 | 104 | 0 | |
| Lewis Run | 892 | 19 | 0 | |
| Commodore | 885 | 379 | 1 | Disinfection Byproducts |
| Pleasantville | 880 | 55 | 3 | E. coli |
| Buck Hill Falls | 876 | 42 | 4 | Fecal Coliform |
| Delaware Water Gap | 850 | 270 | 4 | Chlorine Dioxide |
| Mc Alisterville | 850 | 173 | 0 | |
| Conneautville | 850 | 101 | 0 | |
| Gifford | 850 | 88 | 4 | Chlorine Dioxide |
| Eldred | 850 | 71 | 0 | |
| Mcclure | 845 | 88 | 0 | |
| Spring Mills | 834 | 1,820 | 16 | Chlorine Dioxide, E. coli |
| Wampum | 832 | 41 | 0 | |
| Skokie | 825 | 54 | 2 | Chlorine Dioxide |
| Ringtown | 823 | 5 | 0 | |
| West Alexander | 820 | 102 | 13 | Chlorine Dioxide, TTHM |
| Lakeville | 819 | 289 | 10 | Chlorine Dioxide |
| Mexico | 818 | 171 | 0 | |
| Alexandria | 815 | 12 | 0 | |
| Beaver Springs | 805 | 31 | 0 | |
| Saylorsburg | 803 | 441 | 25 | Chlorine Dioxide, E. coli |
| Fishertown | 801 | 18 | 2 | Chlorine Dioxide |
| Wood | 800 | 404 | 1 | Fecal Coliform |
| Gray | 800 | 262 | 0 | |
| Aspers | 800 | 21 | 4 | Chlorine Dioxide, Fecal Coliform |
| Hulmeville | 750 | 20 | 0 | |
| Warriors Mark | 750 | 30 | 0 | |
| Hidden Valley | 750 | 30 | 1 | Disinfection Byproducts |
| Tannersville | 739 | 318 | 16 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Orefield | 738 | 44 | 0 | |
| Gratz | 738 | 75 | 0 | |
| Berwyn | 732 | 191 | 11 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Penns Creek | 725 | 539 | 0 | |
| Salisbury | 725 | 108 | 0 | |
| North Warren | 721 | 70 | 0 | |
| Alum Bank | 715 | 21 | 1 | Chlorine Dioxide |
| Olyphant | 706 | 650 | 54 | Barium, Chlorine Dioxide, Disinfection Byproducts +1 more |
| Franklintown | 705 | 13 | 0 | |
| Etters | 701 | 29 | 0 | |
| Wyalusing | 700 | 53 | 0 | |
| Fombell | 700 | 45 | 1 | Disinfection Byproducts |
| Summerville | 700 | 239 | 0 | |
| Sigel | 700 | 126 | 0 | |
| Austin | 700 | 72 | 0 | |
| Millerstown | 700 | 18 | 0 | |
| Lawrenceville | 691 | 518 | 2 | Chlorine Dioxide |
| Tionesta | 690 | 12 | 0 | |
| Freeburg | 685 | 98 | 34 | Fecal Coliform, Selenium |
| Butler | 684 | 246 | 0 | |
| Jamestown | 680 | 24 | 1 | E. coli |
| Gap | 672 | 527 | 3 | Chlorine Dioxide |
| Petersburg | 650 | 336 | 0 | |
| Parkesburg | 648 | 103 | 10 | Chlorine Dioxide, Disinfection Byproducts |
| Confluence | 645 | 197 | 33 | Bromate |
| Hooversville | 645 | 149 | 8 | Contaminant 2920, E. coli |
| Osterburg | 642 | 159 | 6 | Chlorine Dioxide, Fecal Coliform |
| Zieglerville | 640 | 139 | 0 | |
| Ulysses | 640 | 591 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Russell | 640 | 24 | 2 | Chlorine Dioxide |
| Cranesville | 638 | 25 | 0 | |
| Berwick | 631 | 1,186 | 10 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Narvon | 626 | 163 | 13 | Chlorine Dioxide, Disinfection Byproducts, HAA5 +1 more |
| Georgetown | 626 | 85 | 0 | |
| Orangeville | 626 | 37 | 1 | Chlorine Dioxide |
| Tioga | 615 | 260 | 0 | |
| Springtown | 600 | 128 | 0 | |
| Dayton | 600 | 116 | 0 | |
| Knoxville | 590 | 216 | 13 | Chlorine Dioxide |
| Mapleton | 570 | 231 | 3 | Bromate, Chlorine Dioxide, Fecal Coliform |
| Susquehanna | 563 | 12 | 0 | |
| Meshoppen | 563 | 485 | 2 | Chlorine Dioxide, Disinfection Byproducts |
| New Enterprise | 558 | 62 | 2 | Chlorine Dioxide, Selenium |
| Clintonville | 557 | 181 | 0 | |
| Kunkletown | 554 | 103 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Shermans Dale | 553 | 73 | 2 | Chlorine Dioxide |
| Aaronsburg | 550 | 195 | 0 | |
| Charlottesville | 550 | 118 | 2 | Chlorine Dioxide |
| New Ringgold | 546 | 39 | 0 | |
| Linden | 540 | 381 | 1 | E. coli |
| Rouseville | 523 | 104 | 2 | Chlorine Dioxide |
| Newell | 520 | 46 | 0 | |
| Frederick | 508 | 24 | 0 | |
| Kennerdell | 502 | 100 | 1 | Disinfection Byproducts |
| Ulster | 500 | 67 | 2 | Disinfection Byproducts, Gross Alpha |
| Lyon Station | 500 | 15 | 0 | |
| Lake Harmony | 500 | 90 | 14 | Chlorine Dioxide |
| Fredonia | 498 | 94 | 5 | Chlorine Dioxide |
| Tremont | 495 | 27 | 1 | Disinfection Byproducts |
| Oak Brook | 491 | 37 | 4 | Chlorine Dioxide |
| Blakeslee | 490 | 30 | 3 | Chlorine Dioxide, E. coli |
| Mountain Top | 482 | 581 | 7 | Chlorine Dioxide, Disinfection Byproducts |
| Allensville | 480 | 68 | 5 | Fecal Coliform |
| Marianna | 480 | 127 | 4 | E. coli, TTHM |
| Mc Veytown | 478 | 45 | 0 | |
| Nottingham | 473 | 212 | 2 | Chlorine Dioxide |
| St Petersburg | 465 | 268 | 13 | Contaminant 2920, E. coli |
| Portersville | 460 | 27 | 0 | |
| Westover | 456 | 296 | 46 | TTHM, Total Haloacetic Acids (HAA5) |
| Templeton | 451 | 68 | 0 | |
| Dalmatia | 450 | 13 | 1 | Chlorine Dioxide |
| Rockton | 450 | 40 | 1 | Total Haloacetic Acids (HAA5) |
| Wattsburg | 450 | 17 | 0 | |
| Genesee | 450 | 1,198 | 15 | Chlorine Dioxide, E. coli, Fecal Coliform |
| Garrett | 449 | 187 | 0 | |
| Three Springs | 442 | 146 | 0 | |
| Cashtown | 441 | 22 | 1 | Disinfection Byproducts |
| Kersey | 440 | 15 | 6 | Total Haloacetic Acids (HAA5) |
| Herndon | 432 | 14 | 0 | |
| Karthaus | 430 | 113 | 0 | |
| Lopez | 425 | 65 | 4 | Chlorine Dioxide, Disinfection Byproducts |
| Rebersburg | 425 | 128 | 5 | E. coli |
| Dingmans Ferry | 422 | 467 | 40 | Chlorine Dioxide |
| Union Dale | 421 | 107 | 8 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Laceyville | 415 | 25 | 0 | |
| Dudley | 403 | 86 | 0 | |
| Willow Street | 401 | 74 | 12 | Chlorine Dioxide, E. coli |
| Dushore | 400 | 98 | 0 | |
| Osceola | 400 | 100 | 1 | Chlorine Dioxide |
| Morris Run | 400 | 11 | 0 | |
| Bullville | 400 | 274 | 16 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Ralston | 400 | 187 | 6 | Chlorine Dioxide |
| West Covina | 400 | 240 | 0 | |
| Wilcox | 396 | 39 | 0 | |
| Fishkill | 366 | 205 | 5 | Chlorine Dioxide |
| Gilbertsville | 365 | 54 | 0 | |
| Montrose | 363 | 529 | 8 | Chlorine Dioxide, E. coli |
| Leraysville | 360 | 13 | 0 | |
| Stump Creek | 354 | 453 | 7 | Chlorine Dioxide |
| Elmhurst Township | 353 | 19 | 3 | Chlorine Dioxide, Disinfection Byproducts |
| Exton | 350 | 143 | 18 | Chlorine Dioxide, E. coli |
| Pheonixville | 350 | 142 | 0 | |
| Broad Top | 350 | 88 | 0 | |
| Saltillo | 350 | 44 | 0 | |
| Cumming | 350 | 693 | 65 | TTHM, Total Haloacetic Acids (HAA5) |
| Glenmoore | 337 | 95 | 0 | |
| New Albany | 336 | 41 | 0 | |
| Loysville | 336 | 393 | 2 | Chlorine Dioxide |
| Montandon | 330 | 340 | 2 | Disinfection Byproducts, E. coli |
| New Cumberland | 330 | 99 | 18 | Chlorine Dioxide, E. coli |
| Laporte | 325 | 21 | 0 | |
| Arnot | 325 | 115 | 6 | Chlorine Dioxide |
| Burnside | 325 | 108 | 3 | Chlorine Dioxide |
| Rew | 325 | 25 | 2 | Chlorine Dioxide |
| Blain | 321 | 21 | 0 | |
| Six Mile Run | 320 | 85 | 0 | |
| Freehold | 315 | 14 | 0 | |
| Pillow | 312 | 22 | 0 | |
| Skytop | 300 | 71 | 1 | Chlorine Dioxide |
| Pocono Manor | 300 | 112 | 1 | Disinfection Byproducts |
| Nelson | 300 | 691 | 50 | Contaminant 2920, Gross Alpha, TTHM +1 more |
| Madison | 300 | 99 | 0 | |
| Rehrersburg | 300 | 16 | 1 | Disinfection Byproducts |
| Coburn | 300 | 80 | 0 | |
| Lucinda | 300 | 7 | 1 | Disinfection Byproducts |
| Knox Dale | 300 | 315 | 0 | |
| Conestoga | 300 | 24 | 0 | |
| Woodbury | 295 | 25 | 3 | E. coli |
| Womelsdorf | 290 | 44 | 5 | Chlorine Dioxide |
| Ellicott City | 290 | 195 | 8 | Chlorine Dioxide, E. coli |
| Fleming | 290 | 29 | 0 | |
| James City | 286 | 11 | 1 | Disinfection Byproducts |
| Mt Pleasant Mills | 285 | 74 | 0 | |
| Lewisberry | 285 | 10 | 0 | |
| Addison | 284 | 112 | 7 | Chlorine Dioxide |
| Hawley | 280 | 96 | 13 | Chlorine Dioxide, E. coli |
| Effort | 279 | 2,004 | 9 | Chlorine Dioxide |
| Dry Run | 278 | 79 | 2 | Chlorine Dioxide |
| Needmore | 276 | 67 | 0 | |
| Havertown | 275 | 1,000 | 37 | Barium, Chlorine Dioxide, E. coli +1 more |
| Brick | 275 | 66 | 1 | E. coli |
| Bangor | 270 | 274 | 10 | Chlorine Dioxide, E. coli |
| North Bend | 270 | 82 | 0 | |
| Newton Hamilton | 270 | 31 | 0 | |
| Ashfield | 266 | 314 | 0 | |
| Glen Campbell | 260 | 34 | 1 | Chlorine Dioxide |
| Driftwood | 258 | 142 | 11 | Fecal Coliform |
| Sacramento | 250 | 64 | 0 | |
| Mary D | 250 | 158 | 5 | Fecal Coliform |
| Cedaredge | 250 | 10 | 0 | |
| Madisonburg | 250 | 3 | 0 | |
| Diamondhead | 250 | 103 | 6 | Chlorine Dioxide, E. coli |
| Harmonsburg | 250 | 319 | 3 | Chlorine Dioxide |
| Fayetteville | 250 | 12 | 0 | |
| Mount Holly Springs | 250 | 7 | 0 | |
| Volant | 245 | 88 | 1 | Chlorine Dioxide |
| Harrisville | 240 | 3 | 0 | |
| Guys Mills | 236 | 181 | 0 | |
| Rixford | 234 | 33 | 0 | |
| Phoenix | 230 | 336 | 0 | |
| Ludlow | 229 | 226 | 0 | |
| Gouldsboro | 225 | 24 | 0 | |
| Shirleysburg | 225 | 125 | 0 | |
| Troxelville | 225 | 25 | 0 | |
| Boyers | 225 | 249 | 4 | Chlorine Dioxide, Disinfection Byproducts |
| Hiawatha | 225 | 249 | 0 | |
| Chestnut Rdg | 225 | 199 | 2 | Chlorine Dioxide |
| Perryville | 224 | 131 | 2 | Cadmium, Chlorine Dioxide |
| Shippingport | 222 | 35 | 20 | TTHM, Total Haloacetic Acids (HAA5) |
| Silver Spring | 217 | 42 | 6 | Chlorine Dioxide |
| Dysart | 216 | 87 | 0 | |
| Defiance | 205 | 308 | 2 | Fecal Coliform |
| Richmond | 200 | 19 | 0 | |
| Dalton | 200 | 509 | 12 | E. coli |
| Randolph | 200 | 239 | 8 | Chlorine Dioxide, E. coli, Gross Alpha |
| Port Clinton | 200 | 20 | 0 | |
| Brandon | 200 | 104 | 2 | Chlorine Dioxide |
| Brave | 200 | 188 | 58 | TTHM |
| Oveido | 200 | 170 | 0 | |
| Greenfield Township | 198 | 218 | 4 | Barium |
| Glen Mills | 196 | 142 | 20 | Chlorine Dioxide |
| Tafton | 186 | 76 | 6 | Chlorine Dioxide |
| Cochranville | 180 | 26 | 0 | |
| Nassau | 180 | 31 | 0 | |
| Sproul | 180 | 519 | 10 | Chlorine Dioxide, Disinfection Byproducts |
| Mifflin | 177 | 47 | 3 | Chlorine Dioxide |
| Barto | 176 | 325 | 5 | Chlorine Dioxide |
| Roaring Brook Twp | 175 | 119 | 30 | Chlorine Dioxide |
| Stevens | 173 | 68 | 1 | Chlorine Dioxide |
| Darlington | 170 | 170 | 14 | Chlorine Dioxide, Disinfection Byproducts, TTHM |
| Mcveytown | 167 | 27 | 0 | |
| Collegeville | 165 | 46 | 9 | Chlorine Dioxide |
| Mount Freedom | 153 | 144 | 0 | |
| Beach Lake | 152 | 150 | 15 | Chlorine Dioxide, E. coli |
| Ransom Twp | 150 | 50 | 5 | Chlorine Dioxide |
| Hazle Township | 150 | 27 | 0 | |
| Gilbert | 150 | 11 | 0 | |
| Martins Creek | 150 | 20 | 0 | |
| Spring Grove | 144 | 90 | 1 | Chlorine Dioxide |
| Bowmansville | 140 | 150 | 4 | Chlorine Dioxide |
| Woodward | 140 | 95 | 4 | Chlorine Dioxide |
| Adamsville | 140 | 547 | 26 | Barium, Chlorine Dioxide |
| Hazel Hurst | 140 | 251 | 5 | Chlorine Dioxide, E. coli |
| Ronks | 140 | 63 | 0 | |
| Manchester | 140 | 6 | 0 | |
| Jenkintown | 139 | 17 | 0 | |
| Dundee | 135 | 161 | 2 | Chlorine Dioxide |
| Holtwood | 133 | 56 | 0 | |
| Hatfield | 130 | 60 | 0 | |
| Rome | 130 | 188 | 1 | E. coli |
| New London | 129 | 10 | 0 | |
| Union | 125 | 239 | 4 | Chlorine Dioxide |
| Fannettsburg | 125 | 237 | 3 | Chlorine Dioxide, E. coli |
| Hood River | 122 | 177 | 2 | Chlorine Dioxide |
| Paradise | 121 | 79 | 2 | Chlorine Dioxide, Selenium |
| Pequea | 121 | 20 | 2 | Selenium |
| Whitehaven | 120 | 1,237 | 0 | |
| Trout Run | 117 | 18 | 1 | Disinfection Byproducts |
| Newfoundland | 115 | 18 | 0 | |
| New Tripoli | 114 | 338 | 10 | Chlorine Dioxide, Disinfection Byproducts |
| Malvern | 112 | 167 | 0 | |
| Palmyra | 112 | 158 | 11 | Chlorine Dioxide, E. coli, Selenium |
| Hershey | 112 | 96 | 4 | Chlorine Dioxide |
| Gillett | 108 | 71 | 2 | Chlorine Dioxide |
| Kimberton | 100 | 36 | 9 | Chlorine Dioxide |
| Henryville | 100 | 213 | 14 | Chlorine Dioxide, E. coli |
| Forksville | 100 | 98 | 7 | Chlorine Dioxide |
| Harford | 100 | 48 | 0 | |
| Hillsdale | 100 | 161 | 5 | Chlorine Dioxide |
Data Sources
Drinking water data from the EPA Safe Drinking Water Information System (SDWIS). Only active community water systems (CWS) serving 100+ people are included.