Water Quality in Wisconsin
1,021 water systems • 566 cities • EPA SDWIS Data
1,021
Water Systems
18,533
Total Violations
2,518
Health-Based Violations
4,230,296
Population Served
Overview
Wisconsin has 1,021 active community water systems serving 4,230,296 people. These systems have accumulated 18,533 EPA Safe Drinking Water Act violations on record, of which 2,518 are health-based violations (meaning a contaminant exceeded safe levels).
Common contaminants found in violations: Chlorine Dioxide, Disinfection Byproducts, Total Organic Carbon, Barium, Chlorine, Selenium, Stage 2 DBP, Endrin, E. coli, Gross Alpha.
Cities with Most Violations in Wisconsin
| # | City | Violations | Health-Based | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Waukesha | 934 | 783 | 7 | 72,340 |
| 2 | Embarrass | 415 | 4 | 1 | 347 |
| 3 | West Bend | 405 | 4 | 5 | 32,624 |
| 4 | Milwaukee | 342 | 20 | 21 | 678,542 |
| 5 | Kenosha | 294 | 13 | 7 | 99,709 |
| 6 | Augusta | 293 | 2 | 1 | 1,450 |
| 7 | Stevens Point | 291 | 31 | 18 | 29,945 |
| 8 | Madison | 247 | 26 | 17 | 285,795 |
| 9 | Pewaukee | 222 | 114 | 10 | 17,799 |
| 10 | Two Rivers | 222 | 3 | 2 | 11,360 |
Largest Cities in Wisconsin
| # | City | Population | Violations | Water Systems |
|---|---|---|---|---|
| 1 | Milwaukee | 678,542 | 342 | 21 |
| 2 | Madison | 285,795 | 247 | 17 |
| 3 | Green Bay | 159,450 | 49 | 6 |
| 4 | Racine | 128,750 | 83 | 4 |
| 5 | Kenosha | 99,709 | 294 | 7 |
| 6 | Appleton | 87,579 | 8 | 3 |
| 7 | Waukesha | 72,340 | 934 | 7 |
| 8 | Eau Claire | 70,899 | 42 | 5 |
| 9 | Oshkosh | 67,076 | 29 | 4 |
| 10 | Janesville | 64,713 | 17 | 2 |
All Cities in Wisconsin
| City | Population | Violations | Health Violations | Contaminants |
|---|---|---|---|---|
| Milwaukee | 678,542 | 342 | 20 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Madison | 285,795 | 247 | 26 | Disinfection Byproducts, E. coli, Stage 2 DBP +1 more |
| Green Bay | 159,450 | 49 | 6 | Chlorine Dioxide, Stage 2 DBP |
| Racine | 128,750 | 83 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Kenosha | 99,709 | 294 | 13 | Chlorine Dioxide, Stage 2 DBP |
| Appleton | 87,579 | 8 | 0 | |
| Waukesha | 72,340 | 934 | 783 | Contaminant 4030, Disinfection Byproducts, E. coli +3 more |
| Eau Claire | 70,899 | 42 | 0 | |
| Oshkosh | 67,076 | 29 | 2 | Stage 2 DBP |
| Janesville | 64,713 | 17 | 1 | Stage 2 DBP |
| West Allis | 63,272 | 8 | 0 | |
| Neenah | 56,433 | 8 | 4 | Disinfection Byproducts, Stage 2 DBP |
| La Crosse | 55,616 | 157 | 6 | Chlorine Dioxide, E. coli, Gross Alpha +1 more |
| Sheboygan | 55,091 | 27 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Wauwatosa | 49,064 | 3 | 0 | |
| Wausau | 46,787 | 75 | 5 | Chlorine, Disinfection Byproducts, Stage 2 DBP |
| Fond Du Lac | 46,472 | 189 | 2 | Stage 2 DBP |
| De Pere | 38,778 | 5 | 3 | Stage 2 DBP, TTHM |
| Beloit | 36,677 | 11 | 8 | Total Organic Carbon |
| Brookfield | 35,909 | 136 | 11 | Chlorine Dioxide, Stage 2 DBP, Total Organic Carbon |
| Manitowoc | 34,735 | 0 | 0 | |
| Sun Prairie | 34,046 | 5 | 3 | Lead |
| West Bend | 32,624 | 405 | 4 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| Oak Creek | 32,436 | 26 | 5 | Stage 2 DBP, TTHM |
| Stevens Point | 29,945 | 291 | 31 | Barium, Chlorine, Chlorine Dioxide +7 more |
| New Berlin | 27,899 | 5 | 0 | |
| Superior | 26,179 | 196 | 17 | Chlorine, Chlorine Dioxide, Disinfection Byproducts +3 more |
| Menomonee Falls | 25,663 | 5 | 1 | E. coli |
| Fitchburg | 25,135 | 7 | 0 | |
| Middleton | 24,234 | 154 | 3 | Endrin, Stage 2 DBP |
| Watertown | 24,111 | 41 | 3 | Total Organic Carbon |
| Franklin | 22,550 | 12 | 0 | |
| Grand Chute | 21,583 | 8 | 0 | |
| South Milwaukee | 21,340 | 47 | 0 | |
| Wisconsin Rapids | 20,976 | 11 | 1 | Stage 2 DBP |
| Menasha | 20,644 | 3 | 0 | |
| Germantown | 20,027 | 52 | 1 | Stage 2 DBP |
| Marshfield | 19,392 | 121 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Cudahy | 18,659 | 4 | 0 | |
| Kaukauna | 18,088 | 17 | 1 | Total Organic Carbon |
| Onalaska | 18,000 | 0 | 0 | |
| Pewaukee | 17,799 | 222 | 114 | Disinfection Byproducts, HAA5, Stage 2 DBP +1 more |
| Ashwaubenon | 17,730 | 1 | 0 | |
| Hudson | 17,635 | 7 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Oconomowoc | 16,666 | 41 | 1 | Stage 2 DBP |
| Mequon | 16,344 | 166 | 9 | Chlorine, Chlorine Dioxide, Stage 2 DBP |
| Beaver Dam | 16,325 | 2 | 0 | |
| Menomonie | 16,123 | 101 | 0 | |
| River Falls | 16,000 | 2 | 1 | Stage 2 DBP |
| Weston | 16,000 | 6 | 0 | |
| Waunakee | 15,999 | 51 | 2 | Disinfection Byproducts, Nitrate-Nitrite |
| Hartford | 15,805 | 1 | 0 | |
| Baraboo | 14,407 | 31 | 0 | |
| Greendale | 14,393 | 12 | 0 | |
| Whitewater | 14,280 | 38 | 2 | Barium |
| Shawano | 14,150 | 7 | 1 | Chlorine Dioxide |
| Verona | 14,030 | 2 | 1 | Stage 2 DBP |
| Plover | 13,636 | 19 | 4 | Chlorine, Chlorine Dioxide |
| Chippewa Falls | 13,622 | 27 | 2 | Selenium, Stage 2 DBP |
| Shorewood | 13,535 | 7 | 1 | Disinfection Byproducts |
| Stoughton | 13,078 | 1 | 0 | |
| Lake Geneva | 12,895 | 57 | 3 | Disinfection Byproducts |
| Glendale | 12,883 | 3 | 0 | |
| Port Washington | 12,853 | 6 | 0 | |
| Brown Deer | 12,741 | 9 | 0 | |
| Grafton | 12,449 | 39 | 4 | Chlorine Dioxide, Stage 2 DBP |
| Fort Atkinson | 12,420 | 18 | 0 | |
| Oregon | 12,324 | 23 | 3 | Selenium, Stage 2 DBP |
| Platteville | 12,268 | 47 | 0 | |
| Little Chute | 12,168 | 11 | 1 | Stage 2 DBP |
| Cedarburg | 11,800 | 2 | 0 | |
| Sussex | 11,781 | 159 | 107 | HAA5, Stage 2 DBP, Total Organic Carbon |
| Greenville | 11,460 | 4 | 1 | Disinfection Byproducts |
| Two Rivers | 11,360 | 222 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Portage | 11,137 | 8 | 1 | Stage 2 DBP |
| Monroe | 11,086 | 26 | 2 | Disinfection Byproducts |
| Burlington | 11,075 | 74 | 3 | Stage 2 DBP, TTHM |
| Pleasant Prairie | 11,054 | 25 | 2 | Stage 2 DBP |
| Marinette | 10,968 | 6 | 0 | |
| New Richmond | 10,824 | 8 | 1 | Stage 2 DBP |
| Elkhorn | 10,507 | 101 | 27 | Barium, Chlorine Dioxide, Contaminant 4020 +2 more |
| Deforest | 10,500 | 2 | 1 | Stage 2 DBP |
| Plymouth | 10,264 | 24 | 2 | Disinfection Byproducts |
| Holmen | 10,264 | 42 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Fort Mccoy | 10,250 | 11 | 1 | Chlorine Dioxide |
| Sparta | 10,025 | 4 | 1 | Disinfection Byproducts |
| Muskego | 10,015 | 53 | 1 | Stage 2 DBP |
| Reedsburg | 9,984 | 0 | 0 | |
| Merrill | 9,831 | 26 | 3 | Chlorine, Gross Alpha |
| Sturgeon Bay | 9,700 | 0 | 0 | |
| Mcfarland | 9,676 | 0 | 0 | |
| Altoona | 9,627 | 13 | 1 | Stage 2 DBP |
| Cottage Grove | 9,345 | 2 | 1 | Stage 2 DBP |
| Hartland | 9,212 | 3 | 0 | |
| Tomah | 9,192 | 23 | 17 | Selenium, Total Organic Carbon |
| Rice Lake | 9,092 | 8 | 0 | |
| Monona | 8,624 | 0 | 0 | |
| Delavan | 8,541 | 21 | 0 | |
| Mukwonago | 8,437 | 215 | 1 | Chlorine Dioxide |
| Sheboygan Falls | 8,365 | 32 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Rhinelander | 8,234 | 2 | 1 | Stage 2 DBP |
| Waupun | 8,056 | 0 | 0 | |
| Ashland | 8,000 | 58 | 31 | Disinfection Byproducts, TTHM, Total Haloacetic Acids (HAA5) |
| Jefferson | 7,926 | 48 | 23 | Disinfection Byproducts, Total Organic Carbon |
| Jackson | 7,844 | 6 | 1 | Stage 2 DBP |
| Antigo | 7,810 | 39 | 8 | Chlorine Dioxide, Stage 2 DBP |
| Mount Horeb | 7,756 | 2 | 1 | Disinfection Byproducts |
| Ripon | 7,716 | 4 | 1 | Stage 2 DBP |
| Kimberly | 7,608 | 3 | 1 | Stage 2 DBP |
| New London | 7,389 | 9 | 0 | |
| Kronenwetter | 6,931 | 4 | 1 | Stage 2 DBP |
| Fox Point | 6,808 | 5 | 1 | Stage 2 DBP |
| Lake Hallie | 6,701 | 15 | 1 | Stage 2 DBP |
| Prairie Du Chien | 6,505 | 14 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Black River Falls | 6,463 | 12 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Edgerton | 6,292 | 20 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Lake Mills | 6,211 | 39 | 8 | Disinfection Byproducts, Total Organic Carbon |
| Waupaca | 6,062 | 7 | 1 | Stage 2 DBP |
| Lodi | 5,902 | 36 | 11 | Barium, Disinfection Byproducts, Stage 2 DBP |
| Union Grove | 5,850 | 68 | 3 | Chlorine, Stage 2 DBP |
| Evansville | 5,835 | 56 | 14 | Chlorine Dioxide, HAA5, Stage 2 DBP +1 more |
| Milton | 5,788 | 10 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Slinger | 5,659 | 4 | 1 | Stage 2 DBP |
| Berlin | 5,524 | 2 | 0 | |
| Mayville | 5,432 | 22 | 9 | Chlorine Dioxide, Stage 2 DBP, Total Organic Carbon |
| West Salem | 5,370 | 21 | 0 | |
| Waterford | 5,368 | 16 | 1 | Stage 2 DBP |
| Richland Center | 5,362 | 189 | 11 | Chlorine Dioxide, Disinfection Byproducts, E. coli +1 more |
| Columbus | 5,173 | 13 | 4 | Disinfection Byproducts |
| Nekoosa | 5,169 | 4 | 0 | |
| East Troy | 5,094 | 19 | 1 | Stage 2 DBP |
| North Fond Du Lac | 5,014 | 19 | 4 | Stage 2 DBP, Total Organic Carbon |
| Windsor | 5,007 | 1 | 0 | |
| Hobart | 4,831 | 28 | 0 | |
| Suamico | 4,697 | 4 | 2 | Total Organic Carbon |
| Clintonville | 4,635 | 20 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Dodgeville | 4,623 | 12 | 0 | |
| Oconto | 4,610 | 3 | 2 | Stage 2 DBP, Total Organic Carbon |
| Prairie Du Sac | 4,606 | 23 | 4 | Selenium, Stage 2 DBP |
| Mosinee | 4,572 | 47 | 2 | Stage 2 DBP |
| Mauston | 4,456 | 3 | 1 | Stage 2 DBP |
| Baldwin | 4,440 | 5 | 0 | |
| Prescott | 4,433 | 7 | 2 | Nitrate-Nitrite |
| Medford | 4,369 | 90 | 4 | Chlorine Dioxide, Disinfection Byproducts |
| Viroqua | 4,362 | 3 | 0 | |
| Saukville | 4,358 | 3 | 1 | Stage 2 DBP |
| Kewaskum | 4,309 | 1 | 0 | |
| Chilton | 4,191 | 8 | 3 | Disinfection Byproducts, Stage 2 DBP |
| Cross Plains | 4,100 | 14 | 0 | |
| Pell Lake | 4,071 | 119 | 6 | Cadmium, Total Organic Carbon |
| Pulaski | 4,040 | 1 | 0 | |
| Kiel | 3,932 | 12 | 3 | Disinfection Byproducts |
| Lancaster | 3,868 | 8 | 0 | |
| Marshall | 3,862 | 5 | 3 | Total Organic Carbon |
| Wrightstown | 3,815 | 8 | 4 | Disinfection Byproducts |
| Arcadia | 3,737 | 0 | 0 | |
| Horicon | 3,682 | 4 | 2 | Chlorine Dioxide |
| Bloomer | 3,680 | 3 | 1 | Stage 2 DBP |
| Sauk City | 3,663 | 13 | 0 | |
| Omro | 3,629 | 6 | 0 | |
| Combined Locks | 3,609 | 12 | 2 | Stage 2 DBP |
| Seymour | 3,601 | 1 | 0 | |
| Waterloo | 3,520 | 19 | 6 | Disinfection Byproducts |
| Wisconsin Dells | 3,507 | 113 | 90 | Chlorine Dioxide, Contaminant 4030, HAA5 +2 more |
| Stanley | 3,500 | 27 | 1 | Chlorine Dioxide |
| Farmington Hills | 3,476 | 143 | 1 | E. coli |
| Barron | 3,423 | 66 | 0 | |
| Peshtigo | 3,420 | 16 | 0 | |
| Johnson Creek | 3,318 | 36 | 1 | Stage 2 DBP |
| Ellsworth | 3,304 | 4 | 1 | Stage 2 DBP |
| Brillion | 3,262 | 6 | 2 | Disinfection Byproducts |
| Freedom | 3,260 | 14 | 0 | |
| Boscobel | 3,237 | 3 | 0 | |
| Algoma | 3,219 | 0 | 0 | |
| Brodhead | 3,216 | 2 | 0 | |
| Rothschild | 3,190 | 2 | 1 | Stage 2 DBP |
| Ladysmith | 3,184 | 10 | 1 | Disinfection Byproducts |
| Tomahawk | 3,180 | 7 | 1 | Stage 2 DBP |
| Sherwood | 3,114 | 17 | 1 | Stage 2 DBP |
| Oostburg | 3,110 | 1 | 0 | |
| Hortonville | 3,028 | 4 | 1 | Stage 2 DBP |
| New Holstein | 3,012 | 18 | 2 | Disinfection Byproducts |
| Park Falls | 2,993 | 6 | 1 | Disinfection Byproducts |
| Amery | 2,962 | 22 | 1 | Stage 2 DBP |
| Spooner | 2,946 | 39 | 0 | |
| Lake Delton | 2,914 | 3 | 0 | |
| Oconto Falls | 2,892 | 2 | 1 | Stage 2 DBP |
| Somerset | 2,854 | 11 | 1 | Stage 2 DBP |
| Kewaunee | 2,848 | 6 | 2 | Disinfection Byproducts |
| Genoa City | 2,796 | 71 | 9 | Disinfection Byproducts |
| Osceola | 2,780 | 30 | 4 | Disinfection Byproducts, Stage 2 DBP |
| Hayward | 2,777 | 92 | 4 | Disinfection Byproducts, Gross Alpha |
| Luxemburg | 2,737 | 8 | 0 | |
| Belleville | 2,712 | 3 | 1 | Stage 2 DBP |
| Lomira | 2,701 | 14 | 2 | Total Organic Carbon |
| Denmark | 2,684 | 15 | 5 | Disinfection Byproducts, Stage 2 DBP |
| Juneau | 2,674 | 18 | 10 | Disinfection Byproducts, Total Organic Carbon |
| Mondovi | 2,667 | 5 | 2 | Chlorine, Chlorine Dioxide |
| Williams Bay | 2,601 | 13 | 1 | Disinfection Byproducts |
| Dousman | 2,580 | 37 | 2 | Stage 2 DBP |
| Westby | 2,544 | 35 | 2 | Disinfection Byproducts, Stage 2 DBP |
| New Lisbon | 2,526 | 11 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Poynette | 2,520 | 9 | 1 | Chlorine Dioxide |
| Deerfield | 2,510 | 1 | 0 | |
| Fennimore | 2,507 | 13 | 0 | |
| Winneconne | 2,502 | 43 | 32 | Disinfection Byproducts, HAA5, Stage 2 DBP +1 more |
| Abbotsford | 2,502 | 13 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Belgium | 2,493 | 2 | 1 | Stage 2 DBP |
| Mineral Point | 2,487 | 6 | 3 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| Pardeeville | 2,464 | 44 | 1 | Disinfection Byproducts |
| Minocqua | 2,429 | 14 | 1 | Stage 2 DBP |
| Neillsville | 2,426 | 26 | 0 | |
| Walworth | 2,384 | 23 | 1 | Chlorine Dioxide |
| New Glarus | 2,348 | 6 | 1 | Stage 2 DBP |
| Cumberland | 2,311 | 3 | 0 | |
| Wautoma | 2,280 | 2 | 0 | |
| Washburn | 2,280 | 7 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Fredonia | 2,279 | 17 | 0 | |
| Kohler | 2,271 | 7 | 0 | |
| Darlington | 2,235 | 4 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Cedar Grove | 2,213 | 0 | 0 | |
| Schofield | 2,205 | 10 | 1 | Disinfection Byproducts |
| Butler | 2,181 | 8 | 0 | |
| Colfax | 2,181 | 101 | 3 | Selenium, Stage 2 DBP |
| Spring Green | 2,145 | 199 | 2 | Chlorine |
| Cuba City | 2,141 | 4 | 1 | Stage 2 DBP |
| Whitehall | 2,120 | 8 | 1 | Stage 2 DBP |
| Clinton | 2,119 | 2 | 0 | |
| North Prairie | 2,100 | 18 | 1 | Chlorine Dioxide |
| St. Croix Falls | 2,079 | 3 | 1 | Chlorine Dioxide |
| Redgranite | 2,019 | 5 | 0 | |
| Crandon | 1,958 | 4 | 1 | Stage 2 DBP |
| Eagle | 1,950 | 30 | 3 | Disinfection Byproducts |
| Chetek | 1,931 | 3 | 0 | |
| Somers | 1,930 | 25 | 0 | |
| Fall River | 1,908 | 9 | 2 | Stage 2 DBP |
| New Franken | 1,907 | 8 | 0 | |
| Trempealeau | 1,888 | 4 | 0 | |
| Hammond | 1,884 | 2 | 0 | |
| Cameron | 1,882 | 50 | 1 | Stage 2 DBP |
| Roberts | 1,872 | 2 | 0 | |
| Durand | 1,868 | 0 | 0 | |
| Port Edwards | 1,866 | 7 | 0 | |
| Weyauwega | 1,856 | 213 | 1 | Disinfection Byproducts |
| Spencer | 1,848 | 15 | 1 | Stage 2 DBP |
| Adams | 1,847 | 7 | 0 | |
| Fontana | 1,839 | 22 | 1 | Stage 2 DBP |
| Colby | 1,829 | 0 | 0 | |
| Campbellsport | 1,825 | 16 | 1 | Disinfection Byproducts |
| Randolph | 1,800 | 25 | 15 | Chlorine, Total Organic Carbon |
| Palmyra | 1,756 | 7 | 0 | |
| Mazomanie | 1,744 | 9 | 0 | |
| Osseo | 1,701 | 0 | 0 | |
| Marathon City | 1,695 | 10 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Galesville | 1,679 | 57 | 2 | Disinfection Byproducts |
| Bangor | 1,660 | 19 | 1 | Chlorine Dioxide |
| Random Lake | 1,654 | 16 | 0 | |
| Stratford | 1,643 | 12 | 1 | Stage 2 DBP |
| Cambridge | 1,638 | 12 | 1 | Stage 2 DBP |
| Thorp | 1,636 | 37 | 3 | Chlorine, Disinfection Byproducts |
| Bonduel | 1,625 | 8 | 0 | |
| Delafield | 1,613 | 85 | 9 | Chlorine, E. coli, Stage 2 DBP |
| Fox Lake | 1,610 | 3 | 1 | Disinfection Byproducts |
| Bristol | 1,599 | 8 | 1 | Disinfection Byproducts |
| Grantsburg | 1,575 | 12 | 0 | |
| Darien | 1,573 | 7 | 0 | |
| Elkhart Lake | 1,567 | 1 | 1 | Disinfection Byproducts |
| Niagara | 1,561 | 9 | 0 | |
| Oxford | 1,550 | 19 | 1 | Chlorine |
| Sharon | 1,549 | 125 | 6 | Disinfection Byproducts |
| Eagle River | 1,530 | 6 | 1 | Stage 2 DBP |
| Brooklyn | 1,524 | 3 | 0 | |
| Cleveland | 1,524 | 10 | 1 | Stage 2 DBP |
| Hurley | 1,515 | 23 | 8 | Chlorine Dioxide, TTHM, Total Haloacetic Acids (HAA5) |
| Independence | 1,500 | 3 | 0 | |
| Black Earth | 1,493 | 3 | 1 | Stage 2 DBP |
| Edgar | 1,491 | 7 | 1 | Stage 2 DBP |
| Orfordville | 1,475 | 2 | 0 | |
| Phillips | 1,473 | 8 | 2 | Stage 2 DBP |
| Muscoda | 1,453 | 7 | 4 | Disinfection Byproducts |
| Augusta | 1,450 | 293 | 2 | Selenium |
| Spring Valley | 1,449 | 87 | 7 | Chlorine Dioxide, Disinfection Byproducts |
| Owen | 1,446 | 42 | 8 | Chlorine, Selenium, Stage 2 DBP |
| Mishicot | 1,432 | 2 | 0 | |
| Cornell | 1,390 | 8 | 2 | Chlorine Dioxide |
| Woodville | 1,386 | 6 | 0 | |
| Hillsboro | 1,385 | 25 | 10 | Chlorine Dioxide, Disinfection Byproducts |
| Markesan | 1,365 | 0 | 0 | |
| Cadott | 1,352 | 0 | 0 | |
| Black Creek | 1,336 | 0 | 0 | |
| Elroy | 1,333 | 1 | 0 | |
| Hazel Green | 1,330 | 79 | 9 | Chlorine, Disinfection Byproducts, E. coli +1 more |
| Montello | 1,329 | 8 | 3 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| Loyal | 1,308 | 2 | 0 | |
| Manawa | 1,300 | 10 | 2 | Disinfection Byproducts |
| Marion | 1,293 | 1 | 0 | |
| Blair | 1,280 | 3 | 2 | Chlorine |
| San Francisco | 1,270 | 19 | 4 | Chlorine Dioxide, Disinfection Byproducts, E. coli |
| Fall Creek | 1,269 | 10 | 1 | Stage 2 DBP |
| Gillett | 1,264 | 1 | 0 | |
| Theresa | 1,262 | 12 | 2 | Chlorine, Stage 2 DBP |
| Barneveld | 1,258 | 10 | 5 | Stage 2 DBP, Total Organic Carbon |
| Florence | 1,250 | 1 | 0 | |
| Iola | 1,249 | 2 | 0 | |
| Frederic | 1,241 | 3 | 0 | |
| King | 1,240 | 8 | 0 | |
| Laona | 1,226 | 51 | 9 | Chlorine, Chlorine Dioxide, Disinfection Byproducts +1 more |
| Shullsburg | 1,222 | 0 | 0 | |
| Monticello | 1,217 | 2 | 1 | Stage 2 DBP |
| Reedsville | 1,200 | 13 | 4 | Chlorine, Disinfection Byproducts, Selenium |
| Wittenberg | 1,200 | 0 | 0 | |
| Green Lake | 1,184 | 30 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Hilbert | 1,176 | 1 | 1 | Disinfection Byproducts |
| Princeton | 1,166 | 9 | 1 | Stage 2 DBP |
| Dickeyville | 1,159 | 119 | 3 | E. coli, Stage 2 DBP |
| Luck | 1,150 | 3 | 0 | |
| Cashton | 1,120 | 1 | 0 | |
| Amherst | 1,119 | 5 | 1 | Stage 2 DBP |
| Dane | 1,117 | 4 | 0 | |
| Potosi | 1,115 | 32 | 9 | Chlorine, Gross Alpha |
| Glenwood City | 1,102 | 2 | 0 | |
| Strum | 1,100 | 11 | 1 | Disinfection Byproducts |
| Elk Mound | 1,099 | 17 | 1 | Disinfection Byproducts |
| Rio | 1,095 | 5 | 1 | Stage 2 DBP |
| Greenwood | 1,079 | 5 | 0 | |
| Turtle Lake | 1,073 | 0 | 0 | |
| Hustisford | 1,063 | 2 | 0 | |
| Clear Lake | 1,061 | 2 | 0 | |
| Oakfield | 1,058 | 6 | 0 | |
| Boyceville | 1,043 | 3 | 1 | Stage 2 DBP |
| Camp Douglas | 1,040 | 8 | 0 | |
| Balsam Lake | 1,031 | 3 | 0 | |
| Crivitz | 1,026 | 14 | 1 | Chlorine Dioxide |
| Athens | 1,025 | 8 | 1 | Chlorine |
| Plainfield | 1,024 | 30 | 1 | Chlorine Dioxide |
| Albany | 1,018 | 7 | 0 | |
| Sister Bay | 1,000 | 2 | 0 | |
| Belmont | 991 | 5 | 1 | Stage 2 DBP |
| Barrington | 990 | 10 | 0 | |
| Benton | 976 | 3 | 0 | |
| Valders | 954 | 1 | 0 | |
| Northbrook | 953 | 22 | 0 | |
| Blue Mounds | 950 | 5 | 0 | |
| Shell Lake | 950 | 7 | 1 | Stage 2 DBP |
| Salem | 945 | 12 | 1 | Stage 2 DBP |
| Rib Lake | 945 | 12 | 4 | Chlorine |
| Friendship | 941 | 13 | 0 | |
| Siren | 941 | 0 | 0 | |
| Iron Ridge | 937 | 1 | 0 | |
| Dresser | 936 | 4 | 0 | |
| Shiocton | 921 | 1 | 0 | |
| Milltown | 915 | 4 | 0 | |
| Centuria | 900 | 2 | 0 | |
| Lone Rock | 895 | 9 | 2 | Disinfection Byproducts, Gross Alpha |
| Montreal | 887 | 27 | 4 | Chlorine, Chlorine Dioxide |
| Arena | 877 | 2 | 0 | |
| Brandon | 872 | 1 | 0 | |
| Allenton | 860 | 4 | 0 | |
| Necedah | 844 | 11 | 1 | Stage 2 DBP |
| Highland | 842 | 1 | 0 | |
| Elm Grove | 840 | 50 | 4 | Disinfection Byproducts |
| Dorchester | 834 | 1 | 1 | Disinfection Byproducts |
| Birnamwood | 832 | 5 | 0 | |
| Arlington | 823 | 14 | 5 | Chlorine, Selenium, Stage 2 DBP |
| Argyle | 823 | 6 | 3 | Chlorine |
| Plain | 822 | 13 | 2 | Stage 2 DBP |
| Cassville | 817 | 12 | 3 | E. coli, Stage 2 DBP |
| Footville | 816 | 1 | 1 | Chlorine |
| Pepin | 816 | 29 | 10 | Chlorine, Chlorine Dioxide, Disinfection Byproducts +1 more |
| Three Lakes | 815 | 32 | 3 | Chlorine Dioxide, E. coli, Stage 2 DBP |
| Blanchardville | 810 | 2 | 0 | |
| Pittsville | 800 | 12 | 0 | |
| Elmwood | 798 | 14 | 0 | |
| Stoddard | 793 | 10 | 3 | Chlorine Dioxide, Stage 2 DBP |
| Alma | 769 | 5 | 0 | |
| Wyocena | 768 | 1 | 0 | |
| Cambria | 767 | 6 | 2 | Total Organic Carbon |
| Claytoon | 765 | 4 | 1 | Stage 2 DBP |
| Coon Valley | 765 | 4 | 1 | Stage 2 DBP |
| Mercer | 760 | 3 | 0 | |
| Wonewoc | 758 | 1 | 0 | |
| Whitelaw | 757 | 9 | 1 | Stage 2 DBP |
| Wabeno | 750 | 1 | 0 | |
| Glidden | 750 | 12 | 2 | Chlorine Dioxide |
| Cedaredge | 748 | 31 | 3 | E. coli, Stage 2 DBP |
| Hales Corners | 744 | 39 | 1 | Stage 2 DBP |
| Tigerton | 740 | 9 | 1 | Stage 2 DBP |
| Mellen | 731 | 8 | 0 | |
| Coleman | 727 | 9 | 0 | |
| Cascade | 719 | 5 | 1 | Disinfection Byproducts |
| Reeseville | 718 | 17 | 5 | Chlorine, Disinfection Byproducts |
| Montfort | 718 | 11 | 5 | Chlorine, Chlorine Dioxide, Stage 2 DBP |
| La Farge | 712 | 1 | 0 | |
| Wauzeka | 711 | 6 | 0 | |
| St Nazianz | 705 | 6 | 0 | |
| Almena | 705 | 24 | 0 | |
| Ridgeway | 690 | 9 | 6 | Total Organic Carbon |
| Bloomington | 682 | 4 | 0 | |
| Viola | 667 | 14 | 0 | |
| Livingston | 664 | 1 | 0 | |
| Prentice | 660 | 88 | 0 | |
| Suring | 659 | 32 | 2 | Chlorine, Stage 2 DBP |
| Ettrick | 656 | 117 | 0 | |
| Norwalk | 653 | 0 | 0 | |
| Webster | 652 | 0 | 0 | |
| Greenleaf | 650 | 4 | 0 | |
| Stockbridge | 650 | 2 | 1 | Stage 2 DBP |
| Rockland | 642 | 7 | 2 | Chlorine |
| Avoca | 637 | 8 | 3 | Chlorine, Stage 2 DBP |
| Eleva | 635 | 156 | 2 | Chlorine, Stage 2 DBP |
| Browsville | 630 | 7 | 2 | HAA5, Stage 2 DBP |
| Bruce | 620 | 4 | 0 | |
| Iron River | 600 | 111 | 1 | Stage 2 DBP |
| Soldiers Grove | 592 | 7 | 0 | |
| Merrillan | 591 | 7 | 1 | Stage 2 DBP |
| North Freedom | 589 | 12 | 2 | Disinfection Byproducts |
| Wausaukee | 585 | 9 | 4 | Selenium, Stage 2 DBP |
| Lena | 585 | 6 | 2 | Stage 2 DBP, Total Organic Carbon |
| South Wayne | 576 | 46 | 0 | |
| Ixonia | 575 | 11 | 1 | Disinfection Byproducts |
| Land O Lakes | 570 | 49 | 6 | Chlorine, Chlorine Dioxide |
| Stetsonville | 563 | 20 | 6 | Chlorine, Disinfection Byproducts, Stage 2 DBP |
| Minong | 561 | 7 | 0 | |
| Kieler | 560 | 2 | 1 | Stage 2 DBP |
| Ontario | 554 | 3 | 1 | Stage 2 DBP |
| Star Prairie | 553 | 5 | 0 | |
| Hatley | 550 | 6 | 0 | |
| Phelps | 550 | 7 | 1 | Chlorine |
| New Auburn | 549 | 5 | 1 | Gross Alpha |
| Bay City | 549 | 14 | 0 | |
| Linden | 547 | 4 | 0 | |
| Merrimac | 547 | 11 | 2 | Disinfection Byproducts, Stage 2 DBP |
| Boyd | 540 | 5 | 0 | |
| Warrens | 540 | 4 | 0 | |
| Gresham | 534 | 59 | 1 | Stage 2 DBP |
| Menomonie Falls | 525 | 0 | 0 | |
| Melrose | 524 | 1 | 1 | E. coli |
| Adell | 510 | 10 | 2 | Chlorine |
| Withee | 506 | 0 | 0 | |
| Waldo | 500 | 0 | 0 | |
| Taylor | 498 | 4 | 0 | |
| St Cloud | 494 | 6 | 0 | |
| Hixton | 493 | 13 | 3 | Chlorine |
| Vesper | 491 | 7 | 0 | |
| Gays Mills | 490 | 15 | 2 | Chlorine Dioxide |
| Wilton | 490 | 4 | 4 | Chlorine |
| Bayfield | 488 | 2 | 0 | |
| Forest Junction | 487 | 9 | 1 | Stage 2 DBP |
| Alma Center | 487 | 34 | 2 | Chlorine Dioxide, Stage 2 DBP |
| Knapp | 486 | 37 | 1 | Chlorine |
| Mt Calvary | 478 | 0 | 0 | |
| Wales | 474 | 2 | 1 | E. coli |
| Lyndon Station | 474 | 39 | 0 | |
| Glenbeulah | 461 | 5 | 1 | Stage 2 DBP |
| Los Angeles | 460 | 76 | 6 | Chlorine Dioxide, Gross Alpha, Stage 2 DBP |
| Cobb | 458 | 34 | 1 | Stage 2 DBP |
| Kendall | 458 | 33 | 6 | Disinfection Byproducts, Stage 2 DBP |
| Coloma | 454 | 9 | 0 | |
| Fairchild | 451 | 8 | 4 | Selenium |
| Orem | 450 | 8 | 2 | E. coli |
| Nashotah | 450 | 6 | 0 | |
| Mattoon | 450 | 16 | 3 | E. coli |
| Cochrane | 450 | 5 | 1 | Chlorine |
| Fountain City | 443 | 10 | 3 | Chlorine, Chlorine Dioxide |
| Birchwood | 442 | 31 | 6 | Chlorine Dioxide, Disinfection Byproducts |
| Sextonville | 425 | 9 | 0 | |
| Blue River | 424 | 1 | 0 | |
| Clyman | 422 | 3 | 2 | Chlorine, Stage 2 DBP |
| Hancock | 419 | 22 | 3 | Chlorine, Chlorine Dioxide |
| Bear Creek | 418 | 10 | 0 | |
| Junction City | 416 | 1 | 0 | |
| Pigeon Falls | 409 | 3 | 0 | |
| Eastman | 407 | 4 | 2 | Chlorine |
| Hinsdale | 400 | 2 | 0 | |
| Elcho | 400 | 13 | 3 | Chlorine, Stage 2 DBP |
| Port Wing | 400 | 4 | 0 | |
| Minneapolis | 399 | 84 | 1 | E. coli |
| Sandy | 396 | 17 | 1 | Disinfection Byproducts |
| Readstown | 395 | 63 | 4 | Chlorine Dioxide, Stage 2 DBP |
| Bayside | 385 | 11 | 0 | |
| Thiensville | 385 | 30 | 0 | |
| Las Vegas | 382 | 37 | 10 | Barium |
| Nelson | 375 | 8 | 0 | |
| Gilman | 372 | 7 | 0 | |
| Chicago | 371 | 218 | 7 | E. coli, Endrin, Stage 2 DBP |
| La Valle | 365 | 19 | 18 | PFOS |
| Fairwater | 365 | 4 | 0 | |
| Dallas | 365 | 117 | 4 | Chlorine Dioxide, Disinfection Byproducts, Stage 2 DBP |
| Bowler | 357 | 2 | 1 | Selenium |
| Maribel | 355 | 3 | 0 | |
| Bagley | 353 | 9 | 2 | Chlorine |
| Oakdale | 352 | 7 | 1 | Chlorine |
| Cazenovia | 351 | 18 | 2 | Chlorine, Stage 2 DBP |
| White Lake | 351 | 0 | 0 | |
| Tampa | 350 | 3 | 0 | |
| Goodman | 350 | 45 | 7 | Chlorine, Chlorine Dioxide, Stage 2 DBP +2 more |
| Pound | 349 | 18 | 8 | Chlorine, Chlorine Dioxide, Stage 2 DBP |
| Granton | 349 | 9 | 1 | Contaminant 2946 |
| Embarrass | 347 | 415 | 4 | Chlorine, Selenium |
| Curtiss | 346 | 8 | 1 | Chlorine Dioxide |
| Friesland | 345 | 12 | 3 | Chlorine Dioxide, Disinfection Byproducts |
| Winter | 344 | 7 | 3 | Chlorine, Stage 2 DBP |
| Lowell | 337 | 9 | 0 | |
| Kennan | 333 | 8 | 1 | Chlorine |
| West Covina | 320 | 19 | 1 | Disinfection Byproducts |
| Wheeler | 317 | 85 | 1 | Stage 2 DBP |
| Irma | 316 | 6 | 0 | |
| Chaseburg | 306 | 3 | 0 | |
| Kellnersville | 301 | 33 | 5 | Disinfection Byproducts, Stage 2 DBP |
| Loganville | 300 | 4 | 0 | |
| Fifield | 300 | 21 | 1 | Disinfection Byproducts |
| Rock Springs | 292 | 6 | 2 | Chlorine, Disinfection Byproducts |
| Rewey | 290 | 34 | 2 | Chlorine, Disinfection Byproducts |
| Haugen | 287 | 12 | 3 | Chlorine, Disinfection Byproducts, Stage 2 DBP |
| Danbury | 286 | 4 | 1 | Stage 2 DBP |
| Hollandale | 283 | 10 | 3 | E. coli |
| Butternut | 283 | 68 | 14 | Chlorine, Chlorine Dioxide, Disinfection Byproducts |
| Milladore | 280 | 0 | 0 | |
| Arbor Vitae | 279 | 35 | 1 | Gross Alpha |
| Nichols | 275 | 3 | 0 | |
| Mindoro | 275 | 10 | 6 | Chlorine Dioxide, Stage 2 DBP |
| Egg Harbor | 265 | 143 | 0 | |
| Sheldon | 265 | 98 | 7 | Chlorine, Chlorine Dioxide, Disinfection Byproducts +1 more |
| Genoa | 264 | 43 | 4 | Chlorine, Chlorine Dioxide, E. coli +1 more |
| Twin Lakes | 259 | 30 | 0 | |
| Browntown | 256 | 28 | 3 | Chlorine, Stage 2 DBP |
| Lavalle | 253 | 21 | 3 | Chlorine, Chlorine Dioxide, Stage 2 DBP |
| Kansasville | 250 | 30 | 0 | |
| Seneca | 250 | 3 | 0 | |
| Downsville | 250 | 3 | 0 | |
| Drummond | 250 | 8 | 2 | Disinfection Byproducts |
| Radisson | 241 | 32 | 2 | E. coli, Stage 2 DBP |
| Weyerhaeuser | 238 | 7 | 2 | Chlorine, Chlorine Dioxide |
| Mt Horeb | 235 | 23 | 0 | |
| Union Center | 225 | 11 | 0 | |
| Gratiot | 224 | 127 | 4 | Chlorine Dioxide, Stage 2 DBP |
| Orlando | 222 | 42 | 0 | |
| Sturtevant | 220 | 11 | 0 | |
| Sinsinawa | 213 | 3 | 0 | |
| Iron Belt | 211 | 10 | 5 | Chlorine, Chlorine Dioxide, E. coli |
| Mt Sterling | 206 | 27 | 6 | Chlorine, Disinfection Byproducts, Stage 2 DBP |
| South Range | 200 | 8 | 1 | Chlorine |
| Exeland | 196 | 1 | 0 | |
| Pence | 191 | 23 | 2 | Chlorine Dioxide, TTHM |
| Mount Hope | 181 | 9 | 2 | Chlorine |
| Stone Lake | 175 | 17 | 0 | |
| Lannon | 172 | 2 | 0 | |
| Troy Center | 170 | 15 | 0 | |
| Wilson | 170 | 12 | 3 | Chlorine Dioxide, Stage 2 DBP |
| Hustler | 170 | 2 | 0 | |
| Patch Grove | 160 | 2 | 0 | |
| Stitzer | 150 | 10 | 4 | Chlorine Dioxide, Stage 2 DBP |
| Diamondhead | 150 | 2 | 0 | |
| Westboro | 150 | 24 | 5 | Chlorine |
| Miami Beach | 146 | 24 | 1 | Disinfection Byproducts |
| Lake Tomahawk | 133 | 3 | 0 | |
| Bloomfield Hills | 130 | 24 | 0 | |
| Mt Pleasant | 125 | 57 | 0 | |
| Maplewood | 122 | 4 | 0 | |
| Plum City | 120 | 8 | 0 | |
| Dodge | 120 | 61 | 16 | Chlorine Dioxide, Disinfection Byproducts |
| Hawkins | 120 | 8 | 1 | Chlorine Dioxide |
| Maiden Rock | 118 | 5 | 2 | Chlorine, Stage 2 DBP |
| Edmund | 110 | 7 | 0 | |
| Tony | 105 | 32 | 4 | Chlorine Dioxide |
| Santa Monica | 100 | 0 | 0 |
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.