Data report · 2026

Wisconsin Water Damage Risk Index

Where in Wisconsin is a house most likely to take on water? We combined Census housing age with ten years of daily weather for 72 of Wisconsin's 72 counties to rank them.

Highest index

Buffalo

Score 73 of 100

Most pipe-freeze nights

Vilas

110 nights ≤ 20°F a year

Oldest housing

Milwaukee

56% built before 1960

Most heavy-rain days

La Crosse

9.2 days ≥ 1 inch a year

< 4141–4747–5454–60≥ 60 index (0–100)

Key findings

The five highest-scoring counties are Buffalo, Pepin, Richland, Vernon, Lafayette. Each combines old housing with harsher-than-average winters or frequent downpours.
Milwaukee County has the oldest housing in the state, with 56% of homes built before 1960, against a county median of 31%.
Vilas County averaged 110 nights a year at 20°F or colder, the most of any county in the data. The county median is 73.
St. Croix County has the newest housing, with 40% of homes built since 2000, which pulls its index down even where winters are cold.

Weather: NOAA nClimGrid-Daily county averages, 2015–2024. Housing: ACS 2020-2024.

All counties

Select a column header to sort.

Rank	County	Index	Freeze nights	Pre-1960 homes	Heavy-rain days	Muggy nights
1	Buffalo	73	73	43%	7.1	19
2	Pepin	70	76	41%	6.8	17
3	Richland	70	65	41%	8.3	18
4	Vernon	70	70	38%	9.1	15
5	Lafayette	68	62	46%	8.4	18
6	Trempealeau	66	73	33%	8.4	18
7	Iowa	65	64	38%	8.5	20
8	La Crosse	64	69	31%	9.2	20
9	Grant	63	62	35%	8.8	23
10	Monroe	63	78	31%	8.8	10
11	Green	62	59	39%	8.1	22
12	Crawford	61	63	32%	9.1	22
13	Waupaca	61	71	35%	7.7	11
14	Wood	61	79	35%	7.3	7
15	Dodge	60	64	42%	6.8	15
16	Green Lake	60	66	38%	7	16
17	Jackson	59	76	31%	8.3	12
18	Clark	57	83	39%	5.5	5
19	Douglas	57	98	40%	4.5	2
20	Fond du Lac	57	65	39%	6.3	16
21	Ashland	56	100	39%	4.3	1
22	Columbia	56	62	35%	7.8	18
23	Iron	56	107	39%	4.2	1
24	Jefferson	55	58	38%	7.1	20
25	Langlade	55	95	39%	5.2	2
26	Rock	55	56	37%	7.2	24
27	Shawano	55	77	34%	6.6	8
28	Chippewa	54	84	31%	6.3	6
29	Lincoln	54	96	36%	5.4	2
30	Sauk	54	65	28%	8.7	17
31	Juneau	53	75	26%	8.9	10
32	Manitowoc	53	62	46%	6.1	11
33	Marathon	52	86	31%	6.2	5
34	Milwaukee	52	47	56%	5.5	24
35	Pierce	52	80	27%	6.4	16
36	Winnebago	52	64	33%	6.9	17
37	Outagamie	51	67	28%	7.9	12
38	Racine	51	49	40%	6	21
39	Waushara	51	68	30%	7.4	11
40	Eau Claire	50	79	30%	6.7	9
41	Marquette	50	67	29%	7.4	14
42	Portage	48	78	25%	7.7	8
43	Kenosha	47	47	34%	6.5	24
44	Kewaunee	47	64	41%	5.4	8
45	Price	46	99	33%	4	1
46	Rusk	46	92	30%	5.5	4
47	Barron	45	91	31%	5.1	5
48	Dunn	45	82	26%	5.8	10
49	Oneida	45	104	24%	6	1
50	Taylor	45	93	31%	5	3
51	Polk	44	89	26%	5.7	9
52	Adams	43	72	14%	8.4	10
53	Sheboygan	43	60	41%	5.2	11
54	Walworth	42	54	30%	6.9	20
55	Florence	41	102	30%	3.3	1
56	Marinette	41	85	32%	4	3
57	Sawyer	41	99	23%	5.5	2
58	Vilas	41	110	21%	5.6	0
59	Dane	40	61	21%	7.8	22
60	St. Croix	40	83	17%	5.8	13
61	Calumet	39	65	22%	7.2	14
62	Forest	38	103	26%	4.6	1
63	Washburn	38	97	23%	5.2	3
64	Burnett	37	93	18%	5.5	6
65	Oconto	37	78	26%	5.5	5
66	Bayfield	36	97	26%	4.1	1
67	Menominee	35	82	10%	6.2	5
68	Brown	31	64	22%	6.3	11
69	Door	26	66	26%	4.7	6
70	Washington	25	65	20%	5.4	11
71	Waukesha	24	56	20%	5.9	15
72	Ozaukee	21	54	25%	5.1	15

Methodology

For each county with weather data, we convert four factors to a percentile rank among those counties (0 = lowest, 100 = highest), then take a weighted average:

Pipe-freeze nights (nights ≤ 20°F / yr), weight 30%
Homes built before 1960 (% of homes), weight 30%
Heavy-rain days (days ≥ 1 in / yr), weight 25%
Muggy nights (nights ≥ 65°F / yr), weight 15%

Freezing weather and old plumbing get the most weight because burst and failing supply lines are among the most common causes of household water damage. Heavy rain drives basement flooding and sewer backups, and warm, muggy nights mark the humid air that lets mold follow. The index is relative: a low score means lower risk than other Wisconsin counties, not no risk.

Limits: weather values are county-wide averages, so hollows, ridges and lakeshores can differ; ACS housing figures are survey estimates; the index doesn't account for floodplains, soil, or local sewer systems. Full details on our data sources page.

Cite this data

You're welcome to use these figures with attribution. Suggested citation:

Local Water & Mold, "Wisconsin Water Damage Risk Index 2026," https://localwatermold.com/wisconsin/wisconsin-water-damage-risk/. Data: U.S. Census Bureau ACS 2020-2024; NOAA nClimGrid-Daily 2015–2024.