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 11.7 pCi/L, based on Airthings measurements across 193 cities.

Updated August 16, 2026

Highest city

11.7pCi/L

Okauchee Lake

Wisconsin city average

3.4pCi/L

across 193 cities

Above action level

52/ 193

cities

Wisconsin Cities Ranked by Indoor Radon Levels
#	Location	Avg level	Monitors	vs action level
1	Okauchee Lake	11.7 pCi/L	8	2.9× over
2	Barneveld	11.2 pCi/L	17	2.8× over
3	New Glarus	10.2 pCi/L	11	2.5× over
4	Luxemburg	9.2 pCi/L	10	2.3× over
5	Plymouth	7.7 pCi/L	12	1.9× over
6	Watertown	7.0 pCi/L	7	1.8× over
7	Eagle	6.9 pCi/L	6	1.7× over
8	Prairie du Chien	6.9 pCi/L	11	1.7× over
9	Altoona	6.2 pCi/L	13	1.5× over
10	Dousman	6.2 pCi/L	17	1.5× over
11	Platteville	6.0 pCi/L	6	1.5× over
12	Rice Lake	5.9 pCi/L	7	1.5× over
13	North Prairie	5.9 pCi/L	7	1.5× over
14	Lake Mills	5.8 pCi/L	8	1.4× over
15	Weston	5.7 pCi/L	13	1.4× over
16	Hartford	5.5 pCi/L	11	1.4× over
17	New Richmond	5.5 pCi/L	13	1.4× over
18	Belleville	5.5 pCi/L	6	1.4× over
19	Wausau	5.4 pCi/L	28	1.4× over
20	Slinger	5.3 pCi/L	14	1.3× over
21	Ripon	5.3 pCi/L	22	1.3× over
22	Mount Horeb	5.2 pCi/L	22	1.3× over
23	Washburn	5.2 pCi/L	7	1.3× over
24	Fort Atkinson	5.1 pCi/L	6	1.3× over
25	Kronenwetter	5.0 pCi/L	6	1.3× over
26	Somerset	5.0 pCi/L	11	1.3× over
27	Sussex	5.0 pCi/L	22	1.2× over
28	Rhinelander	4.9 pCi/L	15	1.2× over
29	Delafield	4.8 pCi/L	10	1.2× over
30	Brown Deer	4.8 pCi/L	9	1.2× over
31	Richfield	4.7 pCi/L	10	1.2× over
32	Mosinee	4.7 pCi/L	6	1.2× over
33	Somers	4.6 pCi/L	6	1.1× over
34	Crandon	4.5 pCi/L	9	1.1× over
35	Baraboo	4.5 pCi/L	9	1.1× over
36	Kimberly	4.5 pCi/L	27	1.1× over
37	Beaver Dam	4.4 pCi/L	19	1.1× over
38	Big Bend	4.4 pCi/L	12	1.1× over
39	Richland Center	4.3 pCi/L	6	1.1× over
40	Kaukauna	4.3 pCi/L	10	1.1× over
41	Prescott	4.2 pCi/L	14	1.1× over
42	Bellevue	4.2 pCi/L	13	1.1× over
43	Merton	4.2 pCi/L	24	1.1× over
44	De Forest	4.2 pCi/L	11	1.0× over
45	Hartland	4.2 pCi/L	18	1.0× over
46	River Falls	4.2 pCi/L	16	1.0× over
47	Lake Geneva	4.2 pCi/L	14	1.0× over
48	Neenah	4.2 pCi/L	28	1.0× over
49	Burlington	4.1 pCi/L	16	1.0× over
50	Hortonville	4.1 pCi/L	13	1.0× over
51	Gillett	4.1 pCi/L	9	1.0× over
52	North Hudson	4.1 pCi/L	9	1.0× over
✓ Below EPA action level (4 pCi/L)
53	Little Round Lake	4.0 pCi/L	10	1.0× under
54	Menomonie	4.0 pCi/L	6	1.0× under
55	Monroe	4.0 pCi/L	11	1.0× under
56	Mazomanie	3.9 pCi/L	10	1.0× under
57	Williams Bay	3.9 pCi/L	16	1.0× under
58	Hales Corners	3.9 pCi/L	26	1.0× under
59	Trempealeau	3.9 pCi/L	12	1.0× under
60	Wales	3.9 pCi/L	15	1.0× under
61	Cross Plains	3.9 pCi/L	20	1.0× under
62	McFarland	3.8 pCi/L	21	1.0× under
63	Edgerton	3.8 pCi/L	15	0.9× under
64	Port Washington	3.7 pCi/L	11	0.9× under
65	Whitewater	3.7 pCi/L	10	0.9× under
66	New Berlin	3.7 pCi/L	47	0.9× under
67	Lake Wisconsin	3.7 pCi/L	9	0.9× under
68	Oconomowoc	3.6 pCi/L	36	0.9× under
69	Pleasant Prairie	3.6 pCi/L	29	0.9× under
70	Grafton	3.5 pCi/L	31	0.9× under
71	Franklin	3.5 pCi/L	31	0.9× under
72	Roberts	3.5 pCi/L	15	0.9× under
73	Oak Creek	3.5 pCi/L	25	0.9× under
74	Wrightstown	3.5 pCi/L	9	0.9× under
75	Muskego	3.5 pCi/L	23	0.9× under
76	Westby	3.4 pCi/L	8	0.9× under
77	Viroqua	3.4 pCi/L	9	0.9× under
78	Kohler	3.4 pCi/L	13	0.8× under
79	Rosendale	3.4 pCi/L	7	0.8× under
80	East Troy	3.4 pCi/L	9	0.8× under
81	Rib Mountain	3.3 pCi/L	18	0.8× under
82	Verona	3.3 pCi/L	91	0.8× under
83	Waukesha	3.3 pCi/L	70	0.8× under
84	Brooklyn	3.3 pCi/L	14	0.8× under
85	Antigo	3.2 pCi/L	18	0.8× under
86	Janesville	3.2 pCi/L	52	0.8× under
87	Lac du Flambeau	3.2 pCi/L	15	0.8× under
88	Appleton	3.1 pCi/L	58	0.8× under
89	Cuba City	3.1 pCi/L	7	0.8× under
90	Franksville	3.1 pCi/L	23	0.8× under
91	Hammond	3.1 pCi/L	6	0.8× under
92	Mequon	3.0 pCi/L	19	0.8× under
93	Greendale	3.0 pCi/L	47	0.7× under
94	Holmen	3.0 pCi/L	16	0.7× under
95	Black River Falls	3.0 pCi/L	6	0.7× under
96	Greenfield	3.0 pCi/L	25	0.7× under
97	Butler	2.9 pCi/L	31	0.7× under
98	Fitchburg	2.9 pCi/L	25	0.7× under
99	Stoughton	2.9 pCi/L	28	0.7× under
100	Prairie du Sac	2.9 pCi/L	7	0.7× under
101	Sturtevant	2.9 pCi/L	21	0.7× under
102	Mukwonago	2.9 pCi/L	14	0.7× under
103	New London	2.9 pCi/L	8	0.7× under
104	Marshfield	2.9 pCi/L	11	0.7× under
105	Beloit	2.8 pCi/L	12	0.7× under
106	Kewaskum	2.8 pCi/L	6	0.7× under
107	Oshkosh	2.8 pCi/L	54	0.7× under
108	South Milwaukee	2.8 pCi/L	8	0.7× under
109	Lake Wazeecha	2.8 pCi/L	7	0.7× under
110	La Crosse	2.8 pCi/L	39	0.7× under
111	Wauwatosa	2.8 pCi/L	65	0.7× under
112	Lannon	2.7 pCi/L	21	0.7× under
113	Oconto Falls	2.7 pCi/L	8	0.7× under
114	Waunakee	2.7 pCi/L	42	0.7× under
115	Brookfield	2.7 pCi/L	63	0.7× under
116	De Pere	2.7 pCi/L	25	0.7× under
117	Onalaska	2.7 pCi/L	19	0.7× under
118	Genoa City	2.7 pCi/L	8	0.7× under
119	Oostburg	2.7 pCi/L	8	0.7× under
120	Rothschild	2.7 pCi/L	6	0.7× under
121	Evansville	2.7 pCi/L	7	0.7× under
122	Stevens Point	2.7 pCi/L	19	0.7× under
123	Bayside	2.6 pCi/L	13	0.7× under
124	Howard	2.6 pCi/L	20	0.7× under
125	Pewaukee	2.6 pCi/L	29	0.7× under
126	West Salem	2.6 pCi/L	13	0.7× under
127	Menomonee Falls	2.6 pCi/L	29	0.7× under
128	Shorewood Hills	2.6 pCi/L	118	0.7× under
129	Spring Green	2.6 pCi/L	6	0.6× under
130	Germantown	2.5 pCi/L	21	0.6× under
131	Racine	2.5 pCi/L	23	0.6× under
132	Eagle River	2.5 pCi/L	15	0.6× under
133	Oregon	2.5 pCi/L	57	0.6× under
134	Middleton	2.5 pCi/L	92	0.6× under
135	Cottage Grove	2.5 pCi/L	17	0.6× under
136	West Allis	2.5 pCi/L	26	0.6× under
137	Monona	2.5 pCi/L	72	0.6× under
138	Windsor	2.5 pCi/L	25	0.6× under
139	Menasha	2.4 pCi/L	13	0.6× under
140	River Hills	2.4 pCi/L	9	0.6× under
141	Cedarburg	2.4 pCi/L	26	0.6× under
142	Sherwood	2.4 pCi/L	9	0.6× under
143	Fond du Lac	2.4 pCi/L	14	0.6× under
144	Kiel	2.3 pCi/L	7	0.6× under
145	Hudson	2.3 pCi/L	10	0.6× under
146	West Bend	2.3 pCi/L	13	0.6× under
147	Saukville	2.3 pCi/L	6	0.6× under
148	Elkhorn	2.3 pCi/L	9	0.6× under
149	Lake Nebagamon	2.2 pCi/L	8	0.6× under
150	Sheboygan	2.2 pCi/L	16	0.6× under
151	Kenosha	2.2 pCi/L	33	0.6× under
152	Amery	2.2 pCi/L	14	0.6× under
153	Madison	2.2 pCi/L	125	0.6× under
154	Sturgeon Bay	2.2 pCi/L	36	0.6× under
155	Jackson	2.2 pCi/L	14	0.5× under
156	Eau Claire	2.1 pCi/L	54	0.5× under
157	Plover	2.1 pCi/L	6	0.5× under
158	Caledonia	2.1 pCi/L	17	0.5× under
159	Siren	2.1 pCi/L	7	0.5× under
160	Elm Grove	2.1 pCi/L	31	0.5× under
161	Shorewood	2.1 pCi/L	28	0.5× under
162	Ellsworth	2.1 pCi/L	6	0.5× under
163	Sun Prairie	2.0 pCi/L	56	0.5× under
164	Maple Bluff	2.0 pCi/L	33	0.5× under
165	Wind Point	2.0 pCi/L	11	0.5× under
166	Luck	2.0 pCi/L	6	0.5× under
167	Thiensville	2.0 pCi/L	18	0.5× under
168	Seymour	2.0 pCi/L	11	0.5× under
169	Saint Francis	1.9 pCi/L	43	0.5× under
170	Fox Point	1.9 pCi/L	29	0.5× under
171	Glendale	1.9 pCi/L	14	0.5× under
172	Bristol	1.9 pCi/L	10	0.5× under
173	Wisconsin Rapids	1.9 pCi/L	12	0.5× under
174	Suamico	1.9 pCi/L	8	0.5× under
175	Chippewa Falls	1.9 pCi/L	22	0.5× under
176	Ashwaubenon	1.8 pCi/L	9	0.5× under
177	Manitowoc	1.8 pCi/L	6	0.5× under
178	Milwaukee	1.8 pCi/L	52	0.5× under
179	Combined Locks	1.8 pCi/L	12	0.4× under
180	Milton	1.7 pCi/L	7	0.4× under
181	Winneconne	1.7 pCi/L	8	0.4× under
182	Allouez	1.7 pCi/L	14	0.4× under
183	Fontana	1.6 pCi/L	9	0.4× under
184	Tomahawk	1.6 pCi/L	6	0.4× under
185	Waterford	1.6 pCi/L	10	0.4× under
186	Cudahy	1.6 pCi/L	7	0.4× under
187	Saint Croix Falls	1.6 pCi/L	9	0.4× under
188	Wisconsin Dells	1.6 pCi/L	7	0.4× under
189	Green Bay	1.5 pCi/L	14	0.4× under
190	Westfield	1.4 pCi/L	10	0.4× under
191	West Milwaukee	1.4 pCi/L	13	0.3× under
192	Kewaunee	1.3 pCi/L	6	0.3× under
193	Whitefish Bay	1.2 pCi/L	23	0.3× under

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