Wisconsin Cities Ranked by Indoor Radon Levels

Measured averages from Airthings devices across Wisconsin, USA. Action level: 4 pCi/L — the threshold at which remediation is recommended.

Okauchee Lake has the highest measured indoor radon in Wisconsin at 11.0 pCi/L, based on Airthings measurements across 214 cities.

Updated October 25, 2026

Highest city

11.0pCi/L

Okauchee Lake

Wisconsin city average

3.4pCi/L

across 214 cities

Above action level

59/ 214

cities

Wisconsin Cities Ranked by Indoor Radon Levels
#	Location	Avg level	vs action level
1	Okauchee Lake	11.0 pCi/L	2.7× over
2	Barneveld	10.9 pCi/L	2.7× over
3	New Glarus	10.2 pCi/L	2.5× over
4	Luxemburg	9.8 pCi/L	2.5× over
5	Plymouth	7.7 pCi/L	1.9× over
6	Watertown	7.0 pCi/L	1.8× over
7	Eagle	6.9 pCi/L	1.7× over
8	Prairie du Chien	6.9 pCi/L	1.7× over
9	Altoona	6.2 pCi/L	1.5× over
10	Dousman	6.2 pCi/L	1.5× over
11	Platteville	6.0 pCi/L	1.5× over
12	Rice Lake	5.9 pCi/L	1.5× over
13	North Prairie	5.9 pCi/L	1.5× over
14	Salem	5.9 pCi/L	1.5× over
15	Lake Mills	5.8 pCi/L	1.4× over
16	Weston	5.7 pCi/L	1.4× over
17	Hartford	5.5 pCi/L	1.4× over
18	Belleville	5.5 pCi/L	1.4× over
19	Como	5.5 pCi/L	1.4× over
20	Wind Lake	5.4 pCi/L	1.4× over
21	Wausau	5.3 pCi/L	1.3× over
22	New Richmond	5.3 pCi/L	1.3× over
23	Slinger	5.3 pCi/L	1.3× over
24	North La Crosse	5.3 pCi/L	1.3× over
25	Ripon	5.3 pCi/L	1.3× over
26	Mount Horeb	5.2 pCi/L	1.3× over
27	Fort Atkinson	5.1 pCi/L	1.3× over
28	Sussex	5.0 pCi/L	1.3× over
29	Kronenwetter	5.0 pCi/L	1.3× over
30	Somerset	4.9 pCi/L	1.2× over
31	Delafield	4.8 pCi/L	1.2× over
32	Little Round Lake	4.8 pCi/L	1.2× over
33	Brown Deer	4.8 pCi/L	1.2× over
34	Rhinelander	4.8 pCi/L	1.2× over
35	Stratford	4.7 pCi/L	1.2× over
36	Richfield	4.7 pCi/L	1.2× over
37	Mosinee	4.7 pCi/L	1.2× over
38	Somers	4.6 pCi/L	1.1× over
39	Waupun	4.6 pCi/L	1.1× over
40	Union Grove	4.6 pCi/L	1.1× over
41	Baraboo	4.5 pCi/L	1.1× over
42	Crandon	4.5 pCi/L	1.1× over
43	Kimberly	4.5 pCi/L	1.1× over
44	Beaver Dam	4.4 pCi/L	1.1× over
45	Big Bend	4.4 pCi/L	1.1× over
46	Merton	4.2 pCi/L	1.1× over
47	De Forest	4.2 pCi/L	1.0× over
48	Hartland	4.2 pCi/L	1.0× over
49	River Falls	4.2 pCi/L	1.0× over
50	Lake Geneva	4.2 pCi/L	1.0× over
51	Washburn	4.2 pCi/L	1.0× over
52	Richland Center	4.2 pCi/L	1.0× over
53	Burlington	4.1 pCi/L	1.0× over
54	Wales	4.1 pCi/L	1.0× over
55	Fond du Lac	4.1 pCi/L	1.0× over
56	Camp Lake	4.1 pCi/L	1.0× over
57	Hortonville	4.1 pCi/L	1.0× over
58	Prescott	4.1 pCi/L	1.0× over
59	Gillett	4.1 pCi/L	1.0× over
✓ Below EPA action level (4 pCi/L)
60	Kaukauna	4.0 pCi/L	1.0× under
61	Menomonie	4.0 pCi/L	1.0× under
62	Bellevue	4.0 pCi/L	1.0× under
63	Mazomanie	3.9 pCi/L	1.0× under
64	North Hudson	3.9 pCi/L	1.0× under
65	Williams Bay	3.9 pCi/L	1.0× under
66	Hales Corners	3.9 pCi/L	1.0× under
67	Neenah	3.9 pCi/L	1.0× under
68	Trempealeau	3.9 pCi/L	1.0× under
69	Cross Plains	3.9 pCi/L	1.0× under
70	McFarland	3.8 pCi/L	1.0× under
71	Monroe	3.8 pCi/L	0.9× under
72	Edgerton	3.8 pCi/L	0.9× under
73	Franklin	3.8 pCi/L	0.9× under
74	Grafton	3.8 pCi/L	0.9× under
75	Whitewater	3.7 pCi/L	0.9× under
76	Campbellsport	3.7 pCi/L	0.9× under
77	Lake Wisconsin	3.7 pCi/L	0.9× under
78	New Berlin	3.7 pCi/L	0.9× under
79	Oconomowoc	3.6 pCi/L	0.9× under
80	Pleasant Prairie	3.6 pCi/L	0.9× under
81	Winneconne	3.6 pCi/L	0.9× under
82	Lac du Flambeau	3.5 pCi/L	0.9× under
83	Kohler	3.5 pCi/L	0.9× under
84	Port Washington	3.5 pCi/L	0.9× under
85	Roberts	3.5 pCi/L	0.9× under
86	Oak Creek	3.5 pCi/L	0.9× under
87	Wrightstown	3.5 pCi/L	0.9× under
88	Muskego	3.5 pCi/L	0.9× under
89	Westby	3.4 pCi/L	0.9× under
90	Viroqua	3.4 pCi/L	0.9× under
91	Waukesha	3.4 pCi/L	0.8× under
92	Rosendale	3.4 pCi/L	0.8× under
93	East Troy	3.4 pCi/L	0.8× under
94	Brooklyn	3.3 pCi/L	0.8× under
95	Whiting	3.3 pCi/L	0.8× under
96	Rib Mountain	3.3 pCi/L	0.8× under
97	Antigo	3.2 pCi/L	0.8× under
98	Janesville	3.2 pCi/L	0.8× under
99	Verona	3.2 pCi/L	0.8× under
100	Oneida	3.1 pCi/L	0.8× under
101	Dodgeville	3.1 pCi/L	0.8× under
102	Stoughton	3.1 pCi/L	0.8× under
103	Hammond	3.1 pCi/L	0.8× under
104	Greendale	3.0 pCi/L	0.8× under
105	Franksville	3.0 pCi/L	0.8× under
106	Appleton	3.0 pCi/L	0.8× under
107	Holmen	3.0 pCi/L	0.8× under
108	Black River Falls	3.0 pCi/L	0.7× under
109	Greenfield	3.0 pCi/L	0.7× under
110	Fitchburg	3.0 pCi/L	0.7× under
111	Butler	2.9 pCi/L	0.7× under
112	Cuba City	2.9 pCi/L	0.7× under
113	Mequon	2.9 pCi/L	0.7× under
114	South Milwaukee	2.9 pCi/L	0.7× under
115	Waunakee	2.9 pCi/L	0.7× under
116	Mukwonago	2.9 pCi/L	0.7× under
117	New London	2.9 pCi/L	0.7× under
118	Kewaskum	2.8 pCi/L	0.7× under
119	Wauwatosa	2.8 pCi/L	0.7× under
120	Brookfield	2.8 pCi/L	0.7× under
121	Lake Wazeecha	2.8 pCi/L	0.7× under
122	Shorewood Hills	2.8 pCi/L	0.7× under
123	Marshfield	2.8 pCi/L	0.7× under
124	Oshkosh	2.8 pCi/L	0.7× under
125	Beloit	2.8 pCi/L	0.7× under
126	Elkhorn	2.8 pCi/L	0.7× under
127	Lannon	2.7 pCi/L	0.7× under
128	Oconto Falls	2.7 pCi/L	0.7× under
129	Prairie du Sac	2.7 pCi/L	0.7× under
130	Howard	2.7 pCi/L	0.7× under
131	Stevens Point	2.7 pCi/L	0.7× under
132	De Pere	2.7 pCi/L	0.7× under
133	Genoa City	2.7 pCi/L	0.7× under
134	Oostburg	2.7 pCi/L	0.7× under
135	Rothschild	2.7 pCi/L	0.7× under
136	Evansville	2.7 pCi/L	0.7× under
137	La Crosse	2.7 pCi/L	0.7× under
138	Bayside	2.6 pCi/L	0.7× under
139	Sturtevant	2.6 pCi/L	0.7× under
140	Pewaukee	2.6 pCi/L	0.7× under
141	Germantown	2.6 pCi/L	0.7× under
142	Nashotah	2.6 pCi/L	0.7× under
143	West Salem	2.6 pCi/L	0.7× under
144	Middleton	2.6 pCi/L	0.6× under
145	Racine	2.6 pCi/L	0.6× under
146	Menomonee Falls	2.6 pCi/L	0.6× under
147	Onalaska	2.6 pCi/L	0.6× under
148	Spring Green	2.5 pCi/L	0.6× under
149	Eagle River	2.5 pCi/L	0.6× under
150	Oregon	2.5 pCi/L	0.6× under
151	Shell Lake	2.5 pCi/L	0.6× under
152	Menasha	2.5 pCi/L	0.6× under
153	West Allis	2.5 pCi/L	0.6× under
154	Monona	2.4 pCi/L	0.6× under
155	River Hills	2.4 pCi/L	0.6× under
156	Cedarburg	2.4 pCi/L	0.6× under
157	Saukville	2.4 pCi/L	0.6× under
158	Sherwood	2.4 pCi/L	0.6× under
159	Jefferson	2.4 pCi/L	0.6× under
160	Siren	2.4 pCi/L	0.6× under
161	Windsor	2.4 pCi/L	0.6× under
162	Cottage Grove	2.4 pCi/L	0.6× under
163	Hayward	2.3 pCi/L	0.6× under
164	Kiel	2.3 pCi/L	0.6× under
165	Hudson	2.3 pCi/L	0.6× under
166	West Bend	2.3 pCi/L	0.6× under
167	Madison	2.3 pCi/L	0.6× under
168	Elm Grove	2.3 pCi/L	0.6× under
169	Lake Nebagamon	2.2 pCi/L	0.6× under
170	Kenosha	2.2 pCi/L	0.6× under
171	Amery	2.2 pCi/L	0.6× under
172	Suamico	2.2 pCi/L	0.6× under
173	Maple Bluff	2.2 pCi/L	0.5× under
174	Tomah	2.2 pCi/L	0.5× under
175	Sturgeon Bay	2.2 pCi/L	0.5× under
176	Jackson	2.1 pCi/L	0.5× under
177	Caledonia	2.1 pCi/L	0.5× under
178	Eau Claire	2.1 pCi/L	0.5× under
179	Little Chute	2.1 pCi/L	0.5× under
180	Shorewood	2.1 pCi/L	0.5× under
181	Sheboygan	2.1 pCi/L	0.5× under
182	Ellsworth	2.1 pCi/L	0.5× under
183	Plover	2.1 pCi/L	0.5× under
184	Fox Point	2.0 pCi/L	0.5× under
185	Sun Prairie	2.0 pCi/L	0.5× under
186	Saint Francis	2.0 pCi/L	0.5× under
187	Wind Point	2.0 pCi/L	0.5× under
188	Luck	2.0 pCi/L	0.5× under
189	Allouez	2.0 pCi/L	0.5× under
190	Thiensville	2.0 pCi/L	0.5× under
191	Seymour	2.0 pCi/L	0.5× under
192	Glendale	1.9 pCi/L	0.5× under
193	Bristol	1.9 pCi/L	0.5× under
194	Wisconsin Rapids	1.9 pCi/L	0.5× under
195	Combined Locks	1.9 pCi/L	0.5× under
196	Chippewa Falls	1.9 pCi/L	0.5× under
197	Ashwaubenon	1.8 pCi/L	0.5× under
198	Milwaukee	1.8 pCi/L	0.5× under
199	Marshall	1.8 pCi/L	0.5× under
200	Fontana	1.8 pCi/L	0.4× under
201	Tomahawk	1.7 pCi/L	0.4× under
202	Milton	1.7 pCi/L	0.4× under
203	Waterford	1.6 pCi/L	0.4× under
204	Cudahy	1.6 pCi/L	0.4× under
205	Manitowoc	1.6 pCi/L	0.4× under
206	Saint Croix Falls	1.6 pCi/L	0.4× under
207	Green Bay	1.5 pCi/L	0.4× under
208	Wisconsin Dells	1.4 pCi/L	0.4× under
209	Westfield	1.4 pCi/L	0.4× under
210	Portage	1.4 pCi/L	0.3× under
211	West Milwaukee	1.4 pCi/L	0.3× under
212	Kewaunee	1.3 pCi/L	0.3× under
213	Sheboygan Falls	1.3 pCi/L	0.3× under
214	Whitefish Bay	1.3 pCi/L	0.3× under

See USA cities ranked by radon level See all States ranked by radon level