PFAS Contamination

PFAS in Wisconsin Drinking Water

Ranked by number of PFAS compounds detected · Data from EPA SDWIS & UCMR

176

Cities Tested

Exceeds Limit

11%

% Exceeds Limit

0.9 compounds

State Avg

▼ 10% vs national

vs National

388

Health Violations

Analysis

PFAS in Wisconsin: what the data shows

Wisconsin has 176 cities with PFAS monitoring data from the EPA's UCMR 5 program. PFAS ("forever chemicals") were detected in 64 of those cities (36%), with a significant share of cities exceeding the EPA's 2024 maximum contaminant levels of 4 ppt. The state average is better than the national average. 19 cities exceed the EPA MCL for at least one PFAS compound. PFAS are linked to cancer, immune system disruption, and developmental issues. The 2024 EPA rule requires water systems exceeding the MCL to notify customers and reduce levels by 2029. PFAS data comes from the EPA's Unregulated Contaminant Monitoring Rule 5 (UCMR 5), which required large water systems to test for 29 PFAS compounds between 2023–2025. Not all systems have completed testing — cities without data may still have PFAS present.

Comparison

Cities exceeding EPA MCL (4 ppt each)

Wisconsin

11%

19 of 176 cities

← ▼ 10% below national rate (better)

National avg

21%

1662 of 7853 cities

City Map

PFAS data across Wisconsin

Each dot is a city, colored by overall water quality grade. PFAS-tested cities are shown; those exceeding the 4 ppt EPA MCL appear in red. Size reflects population served.

Worst Offenders

Top 10 cities by pfas level in Wisconsin

Highest PFAS levels (compounds)

All Cities

All Wisconsin cities ranked by pfas level

#	City	Level	Exceeds?	Violations	Grade
1	Pewaukee	11 compounds	Yes	71	F
2	Saukville	9 compounds	Yes	0	B
3	Weston	8 compounds	Yes	0	B+
4	La Crosse	7 compounds	Yes	34	F
5	Wausau	7 compounds	Yes	24	C
6	Marshfield	7 compounds	Yes	9	C-
7	Hartland	6 compounds	Yes	8	B
8	Prescott	6 compounds	Yes	8	B+
9	Schofield	6 compounds	Yes	2	B
10	Sheboygan	5 compounds	No	1	A-
11	Brookfield	5 compounds	No	32	C-
12	Monona	5 compounds	No	1	A
13	Tomahawk	5 compounds	Yes	3	B
14	Hartford	4 compounds	Yes	2	B+
15	Rhinelander	4 compounds	Yes	5	B
16	Lake Geneva	3 compounds	Yes	24	C
17	Tomah	3 compounds	No	18	B+
18	Waupaca	3 compounds	Yes	3	B-
19	Slinger	3 compounds	No	2	B
20	Medford	3 compounds	Yes	9	C+
21	Madison	2 compounds	No	14	F
22	Eau Claire	2 compounds	No	18	D+
23	West Bend	2 compounds	Yes	11	F
24	Hudson	2 compounds	No	4	B
25	Oconomowoc	2 compounds	No	13	B
26	Mount Horeb	2 compounds	No	1	A
27	Prairie Du Chien	2 compounds	Yes	9	B
28	Kewaskum	2 compounds	Yes	0	A
29	Palmyra	2 compounds	Yes	5	A-
30	Menasha	1 compounds	No	1	B+
31	Fond Du Lac	1 compounds	No	51	F
32	De Pere	1 compounds	No	38	B
33	Beloit	1 compounds	No	2	B+
34	Germantown	1 compounds	No	8	B-
35	Chippewa Falls	1 compounds	No	12	D+
36	Onalaska	1 compounds	No	2	A-
37	Kaukauna	1 compounds	No	9	B+
38	Verona	1 compounds	No	1	B+
39	Plover	1 compounds	No	9	B+
40	Stoughton	1 compounds	No	4	B+
41	Appleton	1 compounds	No	4	B+
42	Grafton	1 compounds	No	12	C+
43	Little Chute	1 compounds	No	1	B+
44	Cedarburg	1 compounds	No	1	B+
45	Black River Falls	1 compounds	No	11	D+
46	Portage	1 compounds	No	9	B
47	Holmen	1 compounds	No	5	B-
48	Reedsburg	1 compounds	No	1	B+
49	Mc Farland	1 compounds	No	1	A+
50	Rice Lake	1 compounds	No	17	F
51	Jackson	1 compounds	No	1	B+
52	Kimberly	1 compounds	No	1	B-
53	Union Grove	1 compounds	No	26	D
54	Oneida	1 compounds	No	3	D
55	Mayville	1 compounds	No	6	A-
56	East Troy	1 compounds	No	1	B
57	North Fond Du Lac	1 compounds	No	6	B
58	Suamico	1 compounds	No	1	A
59	Oconto	1 compounds	No	3	A-
60	Combined Locks	1 compounds	No	1	B
61	Peshtigo	1 compounds	No	18	A-
62	Ellsworth	1 compounds	No	6	B+
63	Lac Du Flambeau	1 compounds	No	1	A
64	Hilbert	1 compounds	No	3	A
65	Milwaukee	0 compounds	No	2	A
66	Green Bay	0 compounds	No	74	D+
67	Racine	0 compounds	No	4	C+
68	Kenosha	0 compounds	No	11	D
69	Waukesha	0 compounds	No	320	D
70	Oshkosh	0 compounds	No	0	A
71	Janesville	0 compounds	No	12	B
72	West Allis	0 compounds	No	0	A-
73	Neenah	0 compounds	No	6	C+
74	Wauwatosa	0 compounds	No	1	B+
75	Glendale	0 compounds	No	1	A-
76	Manitowoc	0 compounds	No	0	B+
77	Sun Prairie	0 compounds	No	4	A
78	Oak Creek	0 compounds	No	5	B
79	Stevens Point	0 compounds	No	14	C+
80	New Berlin	0 compounds	No	14	B
81	Superior	0 compounds	No	17	F
82	Menomonee Falls	0 compounds	No	6	B+
83	Fitchburg	0 compounds	No	0	A
84	Watertown	0 compounds	No	10	D
85	Middleton	0 compounds	No	3	C+
86	Franklin	0 compounds	No	10	B
87	Caledonia	0 compounds	No	1	B
88	Grand Chute	0 compounds	No	2	A
89	South Milwaukee	0 compounds	No	0	A-
90	Wisconsin Rapids	0 compounds	No	6	B-
91	Cudahy	0 compounds	No	0	B+
92	Menomonie	0 compounds	No	30	F
93	Beaver Dam	0 compounds	No	11	A-
94	Mequon	0 compounds	No	21	F
95	River Falls	0 compounds	No	14	C+
96	Waunakee	0 compounds	No	11	B-
97	Greendale	0 compounds	No	1	A-
98	Shawano	0 compounds	No	11	A
99	Whitewater	0 compounds	No	22	C+
100	Whitefish Bay	0 compounds	No	0	B+
101	Shorewood	0 compounds	No	1	A-
102	Port Washington	0 compounds	No	6	B+
103	Baraboo	0 compounds	No	0	B
104	Brown Deer	0 compounds	No	5	A
105	Fort Atkinson	0 compounds	No	14	A-
106	Platteville	0 compounds	No	11	D+
107	Oregon	0 compounds	No	12	D+
108	Plymouth	0 compounds	No	8	C+
109	Sussex	0 compounds	No	70	D+
110	Waupun	0 compounds	No	22	C+
111	Greenville	0 compounds	No	1	A
112	Two Rivers	0 compounds	No	5	C-
113	New Richmond	0 compounds	No	15	B
114	Monroe	0 compounds	No	9	A-
115	Marinette	0 compounds	No	0	A-
116	Muskego	0 compounds	No	36	D
117	Pleasant Prairie	0 compounds	No	7	B+
118	Burlington	0 compounds	No	27	B-
119	Deforest	0 compounds	No	4	B+
120	Altoona	0 compounds	No	15	C+
121	Elkhorn	0 compounds	No	19	F
122	Fort Mccoy	0 compounds	No	4	B+
123	Sparta	0 compounds	No	2	B
124	Merrill	0 compounds	No	7	C-
125	Sturgeon Bay	0 compounds	No	8	B+
126	Delavan	0 compounds	No	6	F
127	Cottage Grove	0 compounds	No	2	A-
128	Mukwonago	0 compounds	No	27	D
129	Sheboygan Falls	0 compounds	No	5	B-
130	Ashland	0 compounds	No	14	D+
131	Jefferson	0 compounds	No	12	B
132	Antigo	0 compounds	No	8	F
133	Ripon	0 compounds	No	1	B+
134	New London	0 compounds	No	2	D+
135	Kronenwetter	0 compounds	No	1	B+
136	Fox Point	0 compounds	No	0	B+
137	Edgerton	0 compounds	No	17	D
138	Lake Mills	0 compounds	No	11	C+
139	Evansville	0 compounds	No	25	C-
140	Keshena	0 compounds	No	6	C+
141	Milton	0 compounds	No	1	A
142	Berlin	0 compounds	No	13	A
143	Waterford	0 compounds	No	13	B
144	West Salem	0 compounds	No	3	B+
145	Richland Center	0 compounds	No	4	B-
146	Columbus	0 compounds	No	8	B
147	Mauston	0 compounds	No	17	F
148	Clintonville	0 compounds	No	15	B
149	Prairie Du Sac	0 compounds	No	12	C+
150	Dodgeville	0 compounds	No	5	A-
151	Baldwin	0 compounds	No	2	A
152	Viroqua	0 compounds	No	2	A-
153	Chilton	0 compounds	No	8	B+
154	Pulaski	0 compounds	No	0	A-
155	Cross Plains	0 compounds	No	3	A-
156	Pell Lake	0 compounds	No	3	C
157	Kiel	0 compounds	No	3	A-
158	Lancaster	0 compounds	No	3	A
159	Marshall	0 compounds	No	3	A
160	Horicon	0 compounds	No	10	B+
161	Bloomer	0 compounds	No	11	B+
162	Omro	0 compounds	No	1	A-
163	Seymour	0 compounds	No	2	A-
164	Waterloo	0 compounds	No	5	A-
165	Sauk City	0 compounds	No	0	A-
166	Stanley	0 compounds	No	2	A
167	Barron	0 compounds	No	1	B+
168	Brillion	0 compounds	No	1	A
169	Bowler	0 compounds	No	8	A-
170	Denmark	0 compounds	No	4	B
171	Bayfield	0 compounds	No	7	C
172	Clinton	0 compounds	No	4	B-
173	Somers	0 compounds	No	1	B+
174	Shullsburg	0 compounds	No	0	A
175	Arena	0 compounds	No	5	C-
176	Bloomington	0 compounds	No	2	A+

FAQ

Frequently asked questions about pfas in Wisconsin

Does Wisconsin tap water contain PFAS?

PFAS were detected in 64 of 176 Wisconsin cities tested under EPA's UCMR 5 program. 19 cities exceed the 2024 EPA MCL of 4 ppt for individual PFAS compounds.

How can I remove PFAS from my drinking water in Wisconsin?

Reverse osmosis (RO) systems are the most effective at removing PFAS, typically removing 90%+ of compounds. High-quality activated carbon block filters (NSF 58-certified for RO, or NSF 53 for solid carbon) also provide significant reduction. Standard pitcher filters vary widely in PFAS removal.

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