Wisconsin tap water quality

1,051 active community water systems.

Largest water systems

Grade	System	People	Health violations (5y)
A	Milwaukee Water Works	626,000	0
B	Madison Water Utility	272,000	1
A	Green Bay Waterworks	107,369	0
A	Racine Waterworks	105,100	0
A	Kenosha Water Utility	99,218	0
A	Appleton Waterworks	74,511	0
D	Waukesha Water Utility	70,718	42
B	Eau Claire Waterworks	70,587	0
A	Janesville Water Utility	64,415	0
A	West Allis Waterworks	63,240	0
A	Oshkosh Waterworks	63,000	0
C	LA Crosse Waterworks	53,000	0
A	Sheboygan Water Utilities	49,931	0
A	Wauwatosa Waterworks	49,064	0
B	Fond Du Lac Waterworks	44,678	1
A	Wausau Waterworks	39,994	0
B	Sun Prairie Utilities	39,300	1
A	City of Beloit	36,677	0
A	North Shore Water Commission	35,598	0
A	Manitowoc Waterworks	34,500	0
B	West Bend Waterworks	32,149	0
B	Oak Creek Waterworks	32,104	1
A	Fitchburg Utility Dist 1	29,900	0
A	Brookfield Water Utility	29,070	0
A	New Berlin Water Utility	27,899	0
A	Neenah Waterworks	27,506	0
A	Stevens Point Waterworks	26,717	0
B	Superior Water Light & Power Company	26,084	1
A	De Pere Waterworks SA 1	25,660	0
A	Watertown Waterworks	23,945	0
C	Middleton Waterworks	23,868	1
A	Menomonee Falls WW - Surface Water	23,867	0
A	Franklin Water Utility	22,500	0
B	Village of Caledonia Water Utility -	21,819	1
A	Grand Chute Tn San Dist 1	21,583	0
A	South Milwaukee Waterworks	21,340	0
C	Howard Waterworks	21,133	2
B	Germantown Water Utility	20,027	1
A	Wis Rapids Water Works & Lighting Comm	20,000	0
C	Marshfield Utilities	18,815	0
A	Cudahy Waterworks	18,659	0
B	Hudson Waterworks	18,558	1
A	Onalaska Waterworks	18,000	0
A	Ashwaubenon Waterworks	17,730	0
A	Kaukauna Utilities	17,493	0
A	Bellevue Waterworks	16,715	0
A	Beaver Dam Water Utility	16,200	0
B	River Falls Waterworks	16,000	1
C	Weston Municipal Utilities	16,000	0
A	Menomonie Waterworks	15,950	0

Most issues (systems serving 10,000+)

Waukesha Water Utility

Serves 70,718 people · Surface water · Full report →

42 health-based violations in the last 5 years; 15 monitoring/reporting violations; 2 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2024).

LA Crosse Waterworks

Serves 53,000 people · Groundwater · Full report →

No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFOA/PFOS average above the 4 ppt federal limit: PFOS, PFOA; Lead 90th percentile below the action level (2026).

Weston Municipal Utilities

Serves 16,000 people · Groundwater · Full report →

No health-based violations in the last 5 years; 1 monitoring/reporting violation; PFOA/PFOS average above the 4 ppt federal limit: PFOS, PFOA; Lead 90th percentile below the action level (2023).

Hartford Waterworks

Serves 15,805 people · Groundwater · Full report →

No health-based violations in the last 5 years; PFOA/PFOS average above the 4 ppt federal limit: PFOS, PFOA; Lead 90th percentile below the action level (2023).

Marshfield Utilities

Serves 18,815 people · Groundwater · Full report →

No health-based violations in the last 5 years; PFOA/PFOS average above the 4 ppt federal limit: PFOS; Other PFAS above 2024 limits (rule proposed for repeal): PFHxS, Hazard Index; Lead 90th percentile below the action level (2025).

Howard Waterworks

Serves 21,133 people · Surface water · Full report →

2 health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Middleton Waterworks

Serves 23,868 people · Groundwater · Full report →

1 health-based violation in the last 5 years; 29 monitoring/reporting violations; 2 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Verona Waterworks

Serves 14,030 people · Groundwater · Full report →

1 health-based violation in the last 5 years; 6 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Holmen Waterworks

Serves 10,147 people · Groundwater · Full report →

1 health-based violation in the last 5 years; 5 monitoring/reporting violations; 2 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Village of Caledonia Water Utility -

Serves 21,819 people · Surface water · Full report →

1 health-based violation in the last 5 years; 3 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Pleasant Prairie Water Utility

Serves 10,754 people · Surface water · Full report →

1 health-based violation in the last 5 years; 3 monitoring/reporting violations; 2 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Hudson Waterworks

Serves 18,558 people · Groundwater · Full report →

1 health-based violation in the last 5 years; 2 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).

Two Rivers Waterworks

Serves 11,270 people · Surface water · Full report →

1 health-based violation in the last 5 years; 2 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile above the new 10 ppb action level (LCRI, effective Nov 1, 2027); Lead 90th percentile below the action level (2025).

Cities

Abbotsford Abrams Adams Adell Afton Albany Algoma Allenton Allouez Alma Alma Center Almena Altoona Amery Amherst Antigo Appleton Arbor Vitae Arcadia Arena Argyle Arlington Ashland Athens Auburndale Augusta Avoca Babcock Bagley Baileys Harbor Baldwin Balsam Lake Bancroft Bangor Baraboo Barneveld Barron Bay City Bayfield Bear Creek Beaver Dam Belgium Belleville Belmont Beloit Benton Berlin Birchwood Birnamwood Black Creek Black Earth Black River Falls Blair Blanchardville Bloomer Bloomington Blue Mounds Blue River Bonduel Boscobel Boulder Junction Bowler Boyceville Boyd Brandon Briggsville Brillion Bristol Brodhead Brokaw Brookfield Brooklyn Brown Deer Brownsville Browntown Bruce Buffalo City Burlington Butler Butternut Cadott Caledonia Cambria Cambridge Cameron Camp Douglas Campbellsport Cascade Cashton Cassville Cazenovia Cecil Cedar Grove Cedarburg Centuria Chaseburg Chetek Chilton Chippewa Falls Clayton Clear Lake Cleveland Clinton Clintonville Clyman Cobb Cochrane Colby Coleman Colfax Coloma Columbus Combined Locks Comstock Conover Coon Valley Cornell Cottage Grove Crandon Crivitz Cross Plains Cuba City Cudahy Cumberland Curtiss Custer Dallas Danbury Dane Darien Darlington De Pere De Soto Deerfield Deforest Delafield Delavan Denmark Dickeyville Dodge Dodgeville Dorchester Dousman Downing Downsville Doylestown Dresser Drummond Dunbar Durand Eagle Eagle River East Ellsworth East Troy Eastman Eau Claire Eau Galle Eden Edgar Edgerton Edmund Egg Harbor Elcho Eleva Elk Mound Elkhart Lake Elkhorn Ellison Bay Ellsworth Elm Grove Elmwood Elroy Embarrass Endeavor Ettrick Evansville Exeland Fairchild Fairwater Fall Creek Fall River Fennimore Fifield Fitchburg Florence Fond Du Lac Fontana Footville Forest Junction Forestville Fort Atkinson Fort McCoy Fountain City Fox Lake Fox Point Franklin Franksville Frederic Fredonia Freedom Fremont Friendship Friesland Galesville Gays Mills Genoa Genoa City Germantown Gile Gillett Gilman Glen Flora Glenbeulah Glendale Glenwood City Glidden Goodman Gordon Gotham Grafton Grand Chute Granton Grantsburg Gratiot Green Bay Green Lake Greendale Greenleaf Greenville Greenwood Gresham Hager City Hales Corners Hammond Hancock Hartford Hartland Hatley Haugen Hawkins Hayward Hazel Green Hazelhurst Hertel Highland Hilbert Hillsboro Hingham Hixton Hobart Hollandale Holmen Horicon Hortonville Houlton Hudson Hull Hurley Hustisford Hustler Independence Iola Irma Iron Belt Iron Ridge Iron River Ixonia Jackson Janesville Jefferson Johnson Creek Junction City Juneau Kansasville Kaukauna Kellnersville Kendall Kenosha Keshena Kewaskum Kewaunee Kiel Kieler Kimberly King Knapp Kohler Kronenwetter LA Crosse LA Farge LA Valle Lac Du Flambeau Lacrosse Ladysmith Lake Delton Lake Geneva Lake Mills Lake Tomahawk Lakewood Lancaster Land O Lakes Lannon Laona Larsen Lena Leroy Linden Little Chute Little Suamico Livingston Lodi Loganville Lomira Lone Rock Lowell Loyal Luck Luxemburg Lyndon Station Madison Maiden Rock Malone Manawa Manitowoc Maplewood Marathon Marathon City Marengo Maribel Marinette Marion Markesan Marquette Marshall Marshfield Mattoon Mauston Mayville Mazomanie Mc Farland Mecan Tn Medford Mellen Melrose Menasha Menomonee Falls Menomonie Mequon Mercer Merrill Merrillan Merrimac Middleton Milladore Milltown Milton Milwaukee Mindoro Mineral Point Minocqua Minong Mishicot Mondovi Monona Monroe Montello Montfort Monticello Montreal Morrisonville Mosinee Mount Calvary Mount Hope Mount Horeb Mount Sterling Mountain Mukwonago Muscoda Muskego Nashotah Necedah Neenah Neillsville Nekoosa Nelson Neopit Neshkoro New Auburn New Berlin New Franken New Glarus New Holstein New Lisbon New London New Richmond Newton Niagara Nichols North Fond Du Lac North Freedom North Lake North Prairie Norwalk Oak Creek Oakdale Oakfield Oconomowoc Oconto Oconto Falls Odanah Ogema Okauchee Omro Onalaska Oneida Ontario Oostburg Oregon Orfordville Osceola Oshkosh Osseo Owen Oxford Packwaukee Paddock Lake Palmyra Pardeeville Park Falls Patch Grove Pearson Pell Lake Pence Pepin Peshtigo Pewaukee Phelps Phillips Pigeon Falls Pittsville Plain Plainfield Platteville Pleasant Prairie Plover Plum City Plymouth Port Edwards Port Washington Port Wing Portage Potosi Pound Powers Lake Poynette Prairie Du Chien Prairie Du Sac Prentice Prescott Princeton Pulaski Racine Radisson Randolph Random Lake Readstown Redgranite Reedsburg Reedsville Reeseville Rewey Rhinelander Rib Lake Rice Lake Richfield Richland Center Ridgeland Ridgeway Rio Ripon River Falls Roberts Rochester Rock Springs Rockland Rothschild Rudolph Saint Cloud Saint Francis Saint Nazianz Salem Sand Creek Sauk City Saukville Saxon Schofield Seneca Sextonville Seymour Sharon Shawano Sheboygan Sheboygan Falls Sheldon Shell Lake Sherwood Shiocton Shorewood Shullsburg Silver Lake Sinsinawa Siren Sister Bay Slinger Soldiers Grove Solon Springs Somers Somerset South Milwaukee South Range South Wayne Sparta Spencer Spooner Spring Green Spring Valley St Cloud St Croix Falls St Nazianz Stanley Star Prairie Stetsonville Stevens Point Stitzer Stockbridge Stoddard Stone Lake Stoughton Stratford Strum Sturgeon Bay Sturtevant Suamico Sullivan Sun Prairie Superior Suring Sussex Taylor Theresa Thiensville Thorp Three Lakes Tigerton Tomah Tomahawk Tony Town of Holland Townsend Trempealeau Trevor Troy Center Turtle Lake Twin Lakes Two Rivers Union Center Union Grove Unity Valders Van Dyne Verona Vesper Viola Viroqua Wabeno Waldo Wales Walworth Warrens Washburn Waterford Waterloo Watertown Waukesha Waunakee Waupaca Waupun Wausau Wausaukee Wautoma Wauwatosa Wauzeka Webster West Allis West Baraboo West Bend West Salem Westboro Westby Westfield Weston Weyauwega Weyerhaeuser Weyerhauser Wheatland Wheeler White Lake Whitefish Bay Whitehall Whitelaw Whitewater Wi Dells Wild Rose Williams Bay Wilmot Wilson Wilton Winchester Windsor Winnebago Winneconne Winter Wisconsin Dells Wisconsin Rapids Withee Wittenberg Wonewoc Woodman Woodruff Woodville Wrightstown Wyocena Yuba Zenda