Wisconsin Water Systems

Compiled by PlainEnviro Editorial, Environmental Data Editorial Team · July 13, 2026

977 community water systems in Wisconsin, ranked by violation count. Data from EPA Safe Drinking Water Information System (SDWIS).

Water Systems

977

Total Violations

2,233

Health Violations

432 systems

Population Served

4,252,230

Wisconsin operates 977 community water systems regulated by the EPA Safe Drinking Water Information System (SDWIS) under the Safe Drinking Water Act. Together these utilities serve an estimated 4,252,230 residents, each filing compliance results with the state's primacy agency and, for federally listed contaminants, with the U.S. Environmental Protection Agency.

Across the state, SDWIS records contain 2,233 total violations, of which 432 systems carry at least one active health-based violation, a Maximum Contaminant Level (MCL) exceedance or treatment-technique failure. That represents roughly 44% of Wisconsin systems.

Violation counts reflect both infrastructure realities and reporting diligence, a state with more small rural systems will accumulate more monitoring-type violations without necessarily delivering worse water. Health-based violations are the stronger safety signal. A past violation does not itself indicate current unsafe water; utilities must notify customers, remediate, and publish an annual Consumer Confidence Report. All numbers below draw directly from the federal SDWIS record.

Which water systems have violations? (242)

#	System Name	City	Source	Violations	Pop. Served	Health
1	WAUKESHA WATER UTILITY Waukesha	Waukesha	Surface Water	779	70,718	Yes
2	SUSSEX VILLAGE HALL & WATER UTILITY Sussex	Sussex	Groundwater	106	11,750	Yes
3	PEWAUKEE VILLAGE WATERWORKS Pewaukee	Pewaukee	Groundwater	59	8,166	Yes
4	PEWAUKEE CITY WATER AND SEWER UTILITY Pewaukee	Pewaukee	Groundwater	53	8,671	Yes
5	WINNECONNE WATERWORKS Winneconne	Winneconne	Groundwater	32	2,502	Yes
6	ASHLAND WATER UTILITY Ashland	Ashland	Surface Water	31	8,000	Yes
7	ELKHORN WATERWORKS Elkhorn	Elkhorn	Groundwater	26	10,317	Yes
8	JEFFERSON WATERWORKS Jefferson	Jefferson	Groundwater	23	7,926	Yes
9	TOMAH WATERWORKS Tomah	Tomah	Groundwater	17	9,192	Yes
10	RANDOLPH WATER DEPT Randolph	Randolph	Groundwater	15	1,800	Yes
11	EVANSVILLE WATERWORKS Evansville	Evansville	Groundwater	12	5,703	Yes
12	WAUPUN CORRECTIONAL INST Madison	Madison	Groundwater	12	3,706	Yes
13	JUNEAU WATERWORKS Juneau	Juneau	Groundwater	10	2,627	Yes
14	HILLSBORO WATERWORKS Hillsboro	Hillsboro	Groundwater	10	1,325	Yes
15	PEPIN WATERWORKS Pepin	Pepin	Groundwater	10	816	Yes
16	GENOA CITY WATERWORKS Genoa City	Genoa City	Groundwater	9	2,766	Yes
17	BELOIT CITY OF Beloit	Beloit	Groundwater	8	36,677	Yes
18	LAKE MILLS WATERWORKS Lake Mills	Lake Mills	Groundwater	8	6,211	Yes
19	HURLEY WATERWORKS Hurley	Hurley	Groundwater	8	1,515	Yes
20	CRYSTAL LAKE RV RESORT LLC Lodi	Lodi	Groundwater	8	725	Yes
21	CLARK CO HEALTH CARE CENTER Owen	Owen	Groundwater	8	510	Yes
22	BROOKFIELD WATER UTILITY Brookfield	Brookfield	Groundwater	7	29,070	Yes
23	ANTIGO WATERWORKS Antigo	Antigo	Groundwater	7	7,780	Yes
24	BLOOMFIELD, VILLAGE OF Pell Lake	Pell Lake	Groundwater	6	4,071	Yes
25	WATERLOO WATERWORKS Waterloo	Waterloo	Groundwater	6	3,520	Yes
26	SHARON WATERWORKS Sharon	Sharon	Groundwater	6	1,549	Yes
27	RIDGEWAY WATERWORKS Ridgeway	Ridgeway	Groundwater	6	690	Yes
28	STETSONVILLE WATERWORKS Stetsonville	Stetsonville	Groundwater	6	563	Yes
29	OAK CREEK WATERWORKS Oak Creek	Oak Creek	Surface Water	5	32,104	Yes
30	DENMARK WATERWORKS Denmark	Denmark	Surface Water	5	2,684	Yes
31	BARNEVELD WATERWORKS Barneveld	Barneveld	Groundwater	5	1,258	Yes
32	ARLINGTON WATERWORKS Arlington	Arlington	Groundwater	5	823	Yes
33	REESEVILLE WATERWORKS Reeseville	Reeseville	Groundwater	5	718	Yes
34	MONTFORT WATERWORKS Montfort	Montfort	Groundwater	5	718	Yes
35	HOWARD WATERWORKS Green Bay	Green Bay	Surface Water	4	21,133	Yes
36	COLUMBUS UTILITIES Columbus	Columbus	Groundwater	4	5,173	Yes
37	NORTH FOND DU LAC WATERWORKS North Fond Du Lac	North Fond Du Lac	Groundwater	4	5,014	Yes
38	WRIGHTSTOWN WATERWORKS Wrightstown	Wrightstown	Surface Water	4	3,815	Yes
39	FOX LAKE CORRECTIONAL INSTITUTION Madison	Madison	Groundwater	4	1,850	Yes
40	MUSCODA WATERWORKS Muscoda	Muscoda	Groundwater	4	1,453	Yes
41	REEDSVILLE WATERWORKS Reedsville	Reedsville	Groundwater	4	1,200	Yes
42	RIB LAKE WATERWORKS Rib Lake	Rib Lake	Groundwater	4	945	Yes
43	MONTREAL WATERWORKS Montreal	Montreal	Groundwater	4	887	Yes
44	WAUSAUKEE WATERWORKS Wausaukee	Wausaukee	Groundwater	4	585	Yes
45	SUN PRAIRIE UTILITIES Sun Prairie	Sun Prairie	Groundwater	3	33,966	Yes
46	SUPERIOR WATER LIGHT & POWER COMPANY Superior	Superior	Surface Water	3	26,084	Yes
47	TWO RIVERS WATERWORKS Two Rivers	Two Rivers	Surface Water	3	11,270	Yes
48	LEDGEVIEW TN SANITARY DIST 2 De Pere	De Pere	Surface Water	3	7,602	Yes
49	CHILTON WATERWORKS Chilton	Chilton	Groundwater	3	4,191	Yes
50	KIEL WATERWORKS Kiel	Kiel	Groundwater	3	3,932	Yes
51	MARSHALL WATERWORKS Marshall	Marshall	Groundwater	3	3,862	Yes
52	LODI WATERWORKS Lodi	Lodi	Groundwater	3	3,146	Yes
53	MINERAL POINT WATERWORKS Mineral Point	Mineral Point	Groundwater	3	2,487	Yes
54	RED CLIFF NORTH Bayfield	Bayfield	Groundwater	3	2,080	Yes
55	EAGLE WATERWORKS Eagle	Eagle	Groundwater	3	1,950	Yes
56	THORP WATERWORKS Thorp	Thorp	Groundwater	3	1,636	Yes
57	MONTELLO WATERWORKS Montello	Montello	Groundwater	3	1,329	Yes
58	LAONA SANITARY DIST Laona	Laona	Groundwater	3	950	Yes
59	ARGYLE WATERWORKS Argyle	Argyle	Groundwater	3	823	Yes
60	STODDARD WATERWORKS Stoddard	Stoddard	Groundwater	3	793	Yes
61	POTOSI WATERWORKS Potosi	Potosi	Groundwater	3	718	Yes
62	AVOCA WATERWORKS Avoca	Avoca	Groundwater	3	637	Yes
63	ROCKY KNOLL HEALTH CARE FAC Sheboygan	Sheboygan	Groundwater	3	564	Yes
64	MADISON WATER UTILITY Madison	Madison	Groundwater	2	272,000	Yes
65	RACINE WATERWORKS Racine	Racine	Surface Water	2	105,100	Yes
66	LA CROSSE WATERWORKS La Crosse	La Crosse	Groundwater	2	53,000	Yes
67	NEENAH WATERWORKS Neenah	Neenah	Surface Water	2	27,506	Yes
68	MARSHFIELD UTILITIES Marshfield	Marshfield	Groundwater	2	18,815	Yes
69	HUDSON WATERWORKS Hudson	Hudson	Groundwater	2	17,635	Yes
70	ALLOUEZ WATERWORKS Green Bay	Green Bay	Surface Water	2	14,156	Yes
71	HOLMEN WATERWORKS Holmen	Holmen	Groundwater	2	10,147	Yes
72	PLYMOUTH UTILITIES Plymouth	Plymouth	Groundwater	2	8,964	Yes
73	EDGERTON WATERWORKS Edgerton	Edgerton	Groundwater	2	5,512	Yes
74	SUAMICO WATERWORKS Suamico	Suamico	Groundwater	2	4,697	Yes
75	CLINTONVILLE UTILITIES Clintonville	Clintonville	Groundwater	2	4,635	Yes
76	OCONTO WATERWORKS Oconto	Oconto	Groundwater	2	4,610	Yes
77	PRESCOTT WATERWORKS Prescott	Prescott	Groundwater	2	4,258	Yes
78	PRAIRIE DU SAC WATERWORKS Prairie Du Sac	Prairie Du Sac	Groundwater	2	4,006	Yes
79	HORICON WATERWORKS Horicon	Horicon	Groundwater	2	3,682	Yes
80	COMBINED LOCKS WATERWORKS Combined Locks	Combined Locks	Groundwater	2	3,609	Yes
81	BRILLION WATERWORKS Brillion	Brillion	Groundwater	2	3,262	Yes
82	WISCONSIN DELLS WATERWORKS Wisconsin Dells	Wisconsin Dells	Groundwater	2	3,232	Yes
83	NEW HOLSTEIN WATERWORKS New Holstein	New Holstein	Groundwater	2	3,012	Yes
84	KEWAUNEE WATERWORKS Kewaunee	Kewaunee	Groundwater	2	2,848	Yes
85	LOMIRA WATERWORKS Lomira	Lomira	Groundwater	2	2,701	Yes
86	MONDOVI WATERWORKS Mondovi	Mondovi	Groundwater	2	2,667	Yes
87	NEW LISBON WATERWORKS New Lisbon	New Lisbon	Groundwater	2	2,526	Yes
88	ABBOTSFORD WATERWORKS Abbotsford	Abbotsford	Groundwater	2	2,502	Yes
89	WASHBURN WATERWORKS Washburn	Washburn	Groundwater	2	2,280	Yes
90	DARLINGTON WATERWORKS Darlington	Darlington	Groundwater	2	2,235	Yes
91	MARATHON CITY WATERWORKS Marathon City	Marathon City	Groundwater	2	1,695	Yes
92	GALESVILLE WATERWORKS Galesville	Galesville	Groundwater	2	1,679	Yes
93	PHILLIPS WATERWORKS Phillips	Phillips	Groundwater	2	1,473	Yes
94	AUGUSTA WATERWORKS Augusta	Augusta	Groundwater	2	1,450	Yes
95	CORNELL WATERWORKS Cornell	Cornell	Groundwater	2	1,390	Yes
96	MANAWA WATERWORKS Manawa	Manawa	Groundwater	2	1,300	Yes
97	BLAIR WATERWORKS Blair	Blair	Groundwater	2	1,280	Yes
98	THERESA WATERWORKS Theresa	Theresa	Groundwater	2	1,262	Yes
99	HAZEL GREEN WATERWORKS Hazel Green	Hazel Green	Groundwater	2	1,193	Yes
100	GREEN LAKE WATERWORKS Green Lake	Green Lake	Groundwater	2	1,002	Yes
101	SOUTHERN WISCONSIN CENTER Union Grove	Union Grove	Groundwater	2	950	Yes
102	LONE ROCK WATERWORKS Lone Rock	Lone Rock	Groundwater	2	895	Yes
103	CASSVILLE WATERWORKS Cassville	Cassville	Groundwater	2	777	Yes
104	CAMBRIA WATERWORKS Cambria	Cambria	Groundwater	2	767	Yes
105	GLIDDEN SANITARY DISTRICT Glidden	Glidden	Groundwater	2	750	Yes
106	ROCKLAND WATERWORKS Rockland	Rockland	Groundwater	2	642	Yes
107	ELEVA WATERWORKS Eleva	Eleva	Groundwater	2	635	Yes
108	BROWNSVILLE WATERWORKS Browsville	Browsville	Groundwater	2	630	Yes
109	NORTH FREEDOM WATERWORKS North Freedom	North Freedom	Groundwater	2	589	Yes
110	LENA WATERWORKS Lena	Lena	Groundwater	2	585	Yes
111	SURING WATERWORKS Suring	Suring	Groundwater	2	559	Yes
112	ADELL WATERWORKS Adell	Adell	Groundwater	2	510	Yes
113	COUNTRY ESTATES SANITARY DISTRICT TOWN OF LYONS 1 Burlington	Burlington	Groundwater	2	500	Yes
114	OSHKOSH WATERWORKS Oshkosh	Oshkosh	Surface Water	1	63,000	Yes
115	FOND DU LAC WATERWORKS Fond Du Lac	Fond Du Lac	Groundwater	1	44,303	Yes
116	WEST BEND WATERWORKS West Bend	West Bend	Groundwater	1	31,752	Yes
117	MIDDLETON WATERWORKS Middleton	Middleton	Groundwater	1	23,868	Yes
118	MENOMONEE FALLS WW - SURFACE WATER Menomonee Falls	Menomonee Falls	Surface Water	1	23,867	Yes
119	CALEDONIA WATER UTILITY - VILLAGE OF Racine	Racine	Surface Water	1	21,819	Yes
120	GERMANTOWN WATER UTILITY Germantown	Germantown	Groundwater	1	20,027	Yes
121	FOX CROSSING UTILITIES WEST Neenah	Neenah	Groundwater	1	18,000	Yes
122	RIVER FALLS WATERWORKS River Falls	River Falls	Groundwater	1	16,000	Yes
123	VERONA WATERWORKS Verona	Verona	Groundwater	1	14,030	Yes
124	SHOREWOOD WATERWORKS Shorewood	Shorewood	Surface Water	1	13,535	Yes
125	PLOVER WATERWORKS Plover	Plover	Groundwater	1	13,486	Yes
126	LITTLE CHUTE WATERWORKS Little Chute	Little Chute	Groundwater	1	12,168	Yes
127	GREENVILLE UTILITIES VIL OF Greenville	Greenville	Groundwater	1	11,340	Yes
128	FOX CROSSING UTILITIES EAST Neenah	Neenah	Surface Water	1	10,927	Yes
129	NEW RICHMOND WATERWORKS New Richmond	New Richmond	Groundwater	1	10,824	Yes
130	PLEASANT PRAIRIE WATER UTILITY Pleasant Prairie	Pleasant Prairie	Surface Water	1	10,754	Yes
131	DEFOREST WATERWORKS Deforest	Deforest	Groundwater	1	10,500	Yes
132	SPARTA WATERWORKS Sparta	Sparta	Groundwater	1	10,025	Yes
133	FORT MCCOY NORTH POST Fort Mccoy	Fort Mccoy	Groundwater	1	10,000	Yes
134	ALTOONA WATERWORKS Altoona	Altoona	Groundwater	1	9,627	Yes
135	COTTAGE GROVE WATERWORKS Cottage Grove	Cottage Grove	Groundwater	1	9,345	Yes
136	RHINELANDER WATER & WASTEWATER Rhinelander	Rhinelander	Groundwater	1	8,234	Yes
137	SHEBOYGAN FALLS UTILITIES Sheboygan Falls	Sheboygan Falls	Surface Water	1	8,165	Yes
138	MUSKEGO WATER UTILITY Muskego	Muskego	Groundwater	1	8,150	Yes
139	JACKSON WATERWORKS Jackson	Jackson	Groundwater	1	7,844	Yes
140	MT HOREB WATERWORKS Mount Horeb	Mount Horeb	Groundwater	1	7,756	Yes
141	RIPON WATER UTILITY Ripon	Ripon	Groundwater	1	7,716	Yes
142	KIMBERLY WATERWORKS Kimberly	Kimberly	Groundwater	1	7,608	Yes
143	LAKE GENEVA UTILITY COMMISSION Lake Geneva	Lake Geneva	Groundwater	1	7,107	Yes
144	KRONENWETTER WATER & SEWER UTILITY Kronenwetter	Kronenwetter	Groundwater	1	6,931	Yes
145	FOX POINT WATERWORKS Fox Point	Fox Point	Surface Water	1	6,808	Yes
146	LAKE HALLIE WATERWORKS VILLAGE OF Lake Hallie	Lake Hallie	Groundwater	1	6,701	Yes
147	WAUPACA WATERWORKS Waupaca	Waupaca	Groundwater	1	6,062	Yes
148	PRAIRIE DU CHIEN WATERWORKS Prairie Du Chien	Prairie Du Chien	Groundwater	1	6,005	Yes
149	SLINGER WATER UTILITY Slinger	Slinger	Groundwater	1	5,659	Yes
150	MILTON WATERWORKS Milton	Milton	Groundwater	1	5,588	Yes
151	WATERFORD WATERWORKS Waterford	Waterford	Groundwater	1	5,368	Yes
152	MAYVILLE WATERWORKS Mayville	Mayville	Groundwater	1	5,112	Yes
153	RICHLAND CENTER WATERWORKS Richland Center	Richland Center	Groundwater	1	5,100	Yes
154	SHAWANO LK SAN DIST 1 Shawano	Shawano	Groundwater	1	4,950	Yes
155	UNION GROVE WATERWORKS Union Grove	Union Grove	Groundwater	1	4,900	Yes
156	MAUSTON WATERWORKS Mauston	Mauston	Groundwater	1	4,456	Yes
157	SAUKVILLE WATERWORKS Saukville	Saukville	Groundwater	1	4,268	Yes
158	BLOOMER WATERWORKS Bloomer	Bloomer	Groundwater	1	3,680	Yes
159	BLACK RIVER FALLS WATERWORKS Black River Falls	Black River Falls	Groundwater	1	3,608	Yes
160	STANLEY WATERWORKS Stanley	Stanley	Groundwater	1	3,500	Yes
161	MOSINEE WATERWORKS Mosinee	Mosinee	Groundwater	1	3,406	Yes
162	JOHNSON CREEK WATERWORKS Johnson Creek	Johnson Creek	Groundwater	1	3,318	Yes
163	ELLSWORTH WATERWORKS Ellsworth	Ellsworth	Groundwater	1	3,304	Yes
164	ROTHSCHILD WATERWORKS Rothschild	Rothschild	Groundwater	1	3,190	Yes
165	LADYSMITH WATERWORKS Ladysmith	Ladysmith	Groundwater	1	3,184	Yes
166	TOMAHAWK WATERWORKS Tomahawk	Tomahawk	Groundwater	1	3,180	Yes
167	SHERWOOD WATERWORKS Sherwood	Sherwood	Surface Water	1	3,114	Yes
168	HORTONVILLE WATER UTILITY Hortonville	Hortonville	Groundwater	1	3,028	Yes
169	PARK FALLS WATERWORKS Park Falls	Park Falls	Groundwater	1	2,993	Yes
170	AMERY WATERWORKS Amery	Amery	Groundwater	1	2,962	Yes
171	OCONTO FALLS WATERWORKS Oconto Falls	Oconto Falls	Groundwater	1	2,892	Yes
172	SOMERSET WATERWORKS Somerset	Somerset	Groundwater	1	2,854	Yes
173	MENDOTA MENTAL HEALTH INST Madison	Madison	Groundwater	1	2,787	Yes
174	BELLEVILLE WATERWORKS Belleville	Belleville	Groundwater	1	2,712	Yes
175	OSCEOLA WATERWORKS Osceola	Osceola	Groundwater	1	2,680	Yes
176	WILLIAMS BAY WATERWORKS Williams Bay	Williams Bay	Groundwater	1	2,601	Yes
177	HAYWARD WATER UTILITY Hayward	Hayward	Groundwater	1	2,552	Yes
178	POYNETTE WATERWORKS Poynette	Poynette	Groundwater	1	2,520	Yes
179	BELGIUM WATERWORKS Belgium	Belgium	Groundwater	1	2,493	Yes
180	WESTBY WATERWORKS Westby	Westby	Groundwater	1	2,400	Yes
181	LAKELAND SANITARY DIST 1 Minocqua	Minocqua	Groundwater	1	2,381	Yes
182	DOUSMAN WATER UTILITY Dousman	Dousman	Groundwater	1	2,350	Yes
183	NEW GLARUS WATERWORKS New Glarus	New Glarus	Groundwater	1	2,348	Yes
184	WALWORTH WATERWORKS Walworth	Walworth	Groundwater	1	2,304	Yes
185	SCHOFIELD WATERWORKS Schofield	Schofield	Groundwater	1	2,205	Yes
186	CUBA CITY WATERWORKS Cuba City	Cuba City	Groundwater	1	2,141	Yes
187	PRAIRIE VILLAGE WATER TRUST North Prairie	North Prairie	Groundwater	1	2,100	Yes
188	ST CROIX FALLS WATERWORKS St. Croix Falls	St. Croix Falls	Groundwater	1	2,079	Yes
189	CRANDON WATERWORKS Crandon	Crandon	Groundwater	1	1,958	Yes
190	WEYAUWEGA WATERWORKS Weyauwega	Weyauwega	Groundwater	1	1,856	Yes
191	SPENCER WATERWORKS Spencer	Spencer	Groundwater	1	1,848	Yes
192	FONTANA WATER UTILITY Fontana	Fontana	Groundwater	1	1,839	Yes
193	CAMPBELLSPORT WATERWORKS Campbellsport	Campbellsport	Groundwater	1	1,825	Yes
194	WHITEHALL WATERWORKS Whitehall	Whitehall	Groundwater	1	1,820	Yes
195	FALL RIVER WATERWORKS Fall River	Fall River	Groundwater	1	1,793	Yes
196	STRATFORD WATERWORKS Stratford	Stratford	Groundwater	1	1,643	Yes
197	CAMBRIDGE WATER & SEWER UTILITY Cambridge	Cambridge	Groundwater	1	1,638	Yes
198	FOX LAKE WATERWORKS Fox Lake	Fox Lake	Groundwater	1	1,610	Yes
199	ELKHART LAKE WATERWORKS Elkhart Lake	Elkhart Lake	Groundwater	1	1,567	Yes
200	FEDERAL CORRECTIONAL INSTITUTION Oxford	Oxford	Groundwater	1	1,550	Yes
201	EAGLE RIVER WATERWORKS Eagle River	Eagle River	Groundwater	1	1,530	Yes
202	CLEVELAND WATERWORKS Cleveland	Cleveland	Groundwater	1	1,524	Yes
203	BANGOR WATERWORKS Bangor	Bangor	Groundwater	1	1,520	Yes
204	BLACK EARTH WATERWORKS Black Earth	Black Earth	Groundwater	1	1,493	Yes
205	EDGAR WATERWORKS Edgar	Edgar	Groundwater	1	1,491	Yes
206	FALL CREEK WATERWORKS Fall Creek	Fall Creek	Groundwater	1	1,269	Yes
207	MONTICELLO WATERWORKS Monticello	Monticello	Groundwater	1	1,217	Yes
208	HILBERT WATERWORKS Hilbert	Hilbert	Groundwater	1	1,176	Yes
209	PRINCETON WATERWORKS Princeton	Princeton	Groundwater	1	1,166	Yes
210	AMHERST WATERWORKS Amherst	Amherst	Groundwater	1	1,119	Yes
211	STRUM WATERWORKS Strum	Strum	Groundwater	1	1,100	Yes
212	OAKHILL CORRECTIONAL INST Oregon	Oregon	Groundwater	1	1,096	Yes
213	RIO WATERWORKS Rio	Rio	Groundwater	1	1,095	Yes
214	BOYCEVILLE WATERWORKS Boyceville	Boyceville	Groundwater	1	1,043	Yes
215	CRIVITZ WATERWORKS Crivitz	Crivitz	Groundwater	1	1,026	Yes
216	ATHENS WATERWORKS Athens	Athens	Groundwater	1	1,025	Yes
217	BELMONT WATERWORKS Belmont	Belmont	Groundwater	1	991	Yes
218	FOND DU LAC TN WATER UTILITY Fond Du Lac	Fond Du Lac	Groundwater	1	980	Yes
219	SHELL LAKE WATERWORKS Shell Lake	Shell Lake	Groundwater	1	950	Yes
220	PADDOCK LAKE WATERWORKS Salem	Salem	Groundwater	1	945	Yes
221	NECEDAH WATERWORKS Necedah	Necedah	Groundwater	1	844	Yes
222	DORCHESTER WATERWORKS Dorchester	Dorchester	Groundwater	1	834	Yes
223	FOOTVILLE WATERWORKS Footville	Footville	Groundwater	1	816	Yes
224	PLAIN WATERWORKS Plain	Plain	Groundwater	1	792	Yes
225	CLAYTON WATERWORKS Claytoon	Claytoon	Groundwater	1	765	Yes
226	COON VALLEY WATERWORKS Coon Valley	Coon Valley	Groundwater	1	765	Yes
227	WHITELAW WATERWORKS Whitelaw	Whitelaw	Groundwater	1	757	Yes
228	TIGERTON WATERWORKS Tigerton	Tigerton	Groundwater	1	740	Yes
229	CASCADE WATERWORKS Cascade	Cascade	Groundwater	1	719	Yes
230	SADDLE RIDGE ESTATES Portage	Portage	Groundwater	1	700	Yes
231	STOCKBRIDGE WATERWORKS Stockbridge	Stockbridge	Groundwater	1	650	Yes
232	MEQUON TRAIL TOWNHOMES Mequon	Mequon	Groundwater	1	615	Yes
233	IRON RIVER SANITARY DISTRICT Iron River	Iron River	Groundwater	1	600	Yes
234	BRISTOL WATERWORKS VILLAGE OF Bristol	Bristol	Groundwater	1	598	Yes
235	AUTUMN RIDGE WATER SYSTEM LLC Ixonia	Ixonia	Groundwater	1	575	Yes
236	KIELER SD NO 1 Kieler	Kieler	Groundwater	1	560	Yes
237	ONTARIO WATERWORKS Ontario	Ontario	Groundwater	1	554	Yes
238	PHELPS SANITARY DISTRICT Phelps	Phelps	Groundwater	1	550	Yes
239	NEW AUBURN WATERWORKS New Auburn	New Auburn	Groundwater	1	549	Yes
240	GRESHAM WATERWORKS Gresham	Gresham	Groundwater	1	534	Yes
241	MERRILLAN WATERWORKS Merrillan	Merrillan	Groundwater	1	531	Yes
242	MELROSE WATERWORKS Melrose	Melrose	Groundwater	1	524	Yes

Systems with No Violations (258)

258 water systems in Wisconsin have zero recorded violations. Showing the 50 largest by population served.

MILWAUKEE WATERWORKS (626,000) GREEN BAY WATERWORKS (107,369) KENOSHA WATER UTILITY (99,218) APPLETON WATERWORKS (74,511) EAU CLAIRE WATERWORKS (70,587) JANESVILLE WATER UTILITY (64,415) WEST ALLIS WATERWORKS (63,240) SHEBOYGAN WATER UTILITIES (49,931) WAUWATOSA WATERWORKS (49,064) WAUSAU WATERWORKS (39,994) NORTH SHORE WATER COMMISSION (35,598) MANITOWOC WATERWORKS (34,500) NEW BERLIN WATER UTILITY (27,899) STEVENS POINT WATERWORKS (26,717) DE PERE WATERWORKS SA 1 (25,660) FITCHBURG UTILITY DIST 1 (24,500) WATERTOWN WATERWORKS (23,945) FRANKLIN WATER UTILITY (22,500) GRAND CHUTE TN SAN DIST 1 (21,583) SOUTH MILWAUKEE WATERWORKS (21,340) WIS RAPIDS WATER WORKS & LIGHTING COMM (20,000) CUDAHY WATERWORKS (18,659) ONALASKA WATERWORKS (18,000) ASHWAUBENON WATERWORKS (17,730) KAUKAUNA UTILITIES (17,493) BELLEVUE WATERWORKS (16,715) BEAVER DAM WATER UTILITY (16,200) WESTON MUNICIPAL UTILITIES (16,000) MENOMONIE WATERWORKS (15,950) HARTFORD WATERWORKS (15,805) OCONOMOWOC WATERWORKS (15,805) MENASHA ELEC & WATER UTIL (15,144) WAUNAKEE WATERWORKS (14,879) GREENDALE WATERWORKS (14,393) WHITEFISH BAY WATERWORKS (14,272) WHITEWATER WATERWORKS (14,000) CHIPPEWA FALLS WATERWORKS (13,375) STOUGHTON WATERWORKS (13,078) DARBOY SANITARY DIST 1 (13,024) GLENDALE WATERWORKS (12,883) PORT WASHINGTON WATERWORKS (12,853) BROWN DEER WATERWORKS (12,741) BARABOO WATERWORKS (12,703) FORT ATKINSON WATERWORKS (12,390) GRAFTON WATERWORKS (12,269) PLATTEVILLE WATERWORKS (12,268) CEDARBURG L & W COMMISSION (11,800) OREGON WATERWORKS (11,200) MEQUON WATER UTILITY (11,152) MARINETTE WATERWORKS (10,968) +208 more

All Water Systems in Wisconsin (977)

Page 4 of 20, ordered by population served.

System	Population Served	Violations
DODGEVILLE WATERWORKS	4,583	0
MAUSTON WATERWORKS	4,456	1
BALDWIN WATERWORKS	4,440	0
VIROQUA WATERWORKS	4,362	0
ONEIDA #1 OR SITE #1	4,322	0
MEDFORD WATERWORKS	4,318	0
KEWASKUM WATERWORKS	4,309	0
SAUKVILLE WATERWORKS	4,268	1
PRESCOTT WATERWORKS	4,258	2
CHILTON WATERWORKS	4,191	3
CROSS PLAINS WATERWORKS	4,100	0
BLOOMFIELD, VILLAGE OF	4,071	6
PULASKI WATERWORKS	4,040	0
PRAIRIE DU SAC WATERWORKS	4,006	2
KESHENA	3,960	0
ALGOMA TN SANITARY DIST 1	3,935	0
KIEL WATERWORKS	3,932	3
LANCASTER WATERWORKS	3,868	0
MARSHALL WATERWORKS	3,862	3
WRIGHTSTOWN WATERWORKS	3,815	4
ARCADIA WATERWORKS	3,737	0
WAUPUN CORRECTIONAL INST	3,706	12
HORICON WATERWORKS	3,682	2
BLOOMER WATERWORKS	3,680	1
HOBART WATERWORKS S A 1	3,670	0
OMRO WATERWORKS	3,629	0
COMBINED LOCKS WATERWORKS	3,609	2
BLACK RIVER FALLS WATERWORKS	3,608	1
SEYMOUR WATERWORKS	3,601	0
WATERLOO WATERWORKS	3,520	6
SAUK CITY WATERWORKS	3,518	0
STANLEY WATERWORKS	3,500	1
BARRON LIGHT & WATER DEPT	3,423	0
PESHTIGO WATERWORKS	3,420	0
MOSINEE WATERWORKS	3,406	1
JOHNSON CREEK WATERWORKS	3,318	1
ELLSWORTH WATERWORKS	3,304	1
BRILLION WATERWORKS	3,262	2
FREEDOM SANITARY DISTRICT	3,260	0
BOSCOBEL WATERWORKS	3,237	0
WISCONSIN DELLS WATERWORKS	3,232	2
ALGOMA WATERWORKS	3,219	0
BRODHEAD WATERWORKS	3,216	0
ROTHSCHILD WATERWORKS	3,190	1
LADYSMITH WATERWORKS	3,184	1
TOMAHAWK WATERWORKS	3,180	1
LAC DU FLAMBEAU	3,168	0
LODI WATERWORKS	3,146	3
SHERWOOD WATERWORKS	3,114	1
OOSTBURG WATERWORKS	3,110	0

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Frequently Asked Questions

How many water systems are in Wisconsin?

Wisconsin has 977 community water systems tracked by the EPA, serving a combined population of 4,252,230 people.

How many water systems in Wisconsin have health violations?

432 water systems in Wisconsin have health-based violations, which include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations. These represent 44% of all systems in the state.

What is the total number of water violations in Wisconsin?

Wisconsin water systems have accumulated 2,233 total violations across all 977 community water systems.

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About This Data

Water system data is from the EPA Safe Drinking Water Information System (SDWIS). Health-based violations include Maximum Contaminant Level (MCL) and Treatment Technique (TT) violations that may pose a direct risk to public health. Only community water systems (CWS) are included.

Source: U.S. Environmental Protection Agency, SDWIS Federal Reporting Services U.S. Environmental Protection Agency, SDWIS Federal Reporting Services

Read our methodology - how this data is sourced, computed, and verified.

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