Data
Water damage risk by state
Old plumbing, hard freezes, heavy rain and humid summers are what turn into water damage and mold claims. Here's how the 25 states we cover compare, built from 2,285 counties of Census housing data and ten years of NOAA daily weather.
| Coldest county | ||||||||
|---|---|---|---|---|---|---|---|---|
| Alabama | 2,337,265 | 42% | 16% | 3 | 36 | 15.4 | 113 | Colbert County (7) |
| Arkansas | 1,394,673 | 40% | 13% | 9 | 52 | 16.1 | 97 | Madison County (18) |
| Georgia | 4,541,835 | 31% | 12% | 3 | 36 | 12.9 | 103 | Fannin County (12) |
| Illinois | 5,457,452 | 63% | 38% | 40 | 82 | 7.2 | 42 | Jo Daviess County (57) |
| Indiana | 2,976,568 | 55% | 31% | 33 | 83 | 7.9 | 41 | Steuben County (41) |
| Iowa | 1,437,699 | 62% | 38% | 59 | 92 | 7.1 | 32 | Dickinson County (81) |
| Kansas | 1,293,635 | 56% | 32% | 32 | 87 | 8.4 | 70 | Thomas County (62) |
| Kentucky | 2,023,116 | 47% | 22% | 19 | 71 | 11.8 | 63 | Lewis County (26) |
| Maryland | 2,265,752 | 47% | 21% | 15 | 73 | 9.2 | 66 | Garrett County (42) |
| Michigan | 4,622,236 | 62% | 36% | 44 | 88 | 4.8 | 23 | Iron County (111) |
| Minnesota | 2,545,030 | 52% | 29% | 84 | 85 | 5.5 | 17 | Cook County (120) |
| Mississippi | 1,341,114 | 41% | 14% | 3 | 30 | 16.8 | 127 | Alcorn County (9) |
| Missouri | 2,651,176 | 51% | 24% | 27 | 75 | 10.4 | 70 | Putnam County (50) |
| Nebraska | 863,444 | 57% | 32% | 56 | 101 | 6.2 | 40 | Sioux County (88) |
| New York | 4,906,755 | 70% | 46% | 40 | 88 | 6.7 | 31 | Hamilton County (91) |
| North Carolina | 4,895,668 | 34% | 14% | 6 | 55 | 11.5 | 84 | Avery County (27) |
| Ohio | 5,292,391 | 63% | 38% | 30 | 79 | 5.6 | 39 | Morrow County (38) |
| Oklahoma | 1,775,127 | 49% | 21% | 13 | 63 | 11.0 | 99 | Cimarron County (42) |
| Pennsylvania | 5,806,452 | 67% | 45% | 29 | 89 | 8.5 | 38 | Potter County (58) |
| South Carolina | 2,443,039 | 33% | 12% | 2 | 35 | 12.4 | 112 | Cherokee County (5) |
| Tennessee | 3,143,670 | 41% | 18% | 10 | 58 | 13.1 | 79 | Johnson County (23) |
| Texas | 12,113,403 | 33% | 12% | 2 | 17 | 11.2 | 153 | Dallam County (37) |
| Virginia | 2,538,662 | 38% | 15% | 14 | 74 | 9.3 | 65 | Highland County (39) |
| West Virginia | 861,325 | 56% | 32% | 25 | 86 | 6.7 | 31 | Pocahontas County (44) |
| Wisconsin | 2,778,572 | 57% | 33% | 64 | 92 | 6.5 | 16 | Vilas County (110) |
Covers counties named "… County" in each state; independent cities and New York City's boroughs aren't included. Housing shares are weighted by housing units. Weather counts are county averages weighted by population, so they describe the typical resident's county. Download the data (CSV)
Why these numbers predict water damage
- Homes built before 1980 are more likely to have galvanized steel supply pipes, cast iron drains and original water heater connections that corrode and fail, and less insulation around pipes in exterior walls and crawl spaces.
- Pipe-freeze nights, lows of 20°F or colder, are when pipes in unheated spaces, exterior walls and crawl spaces are at serious risk of freezing and splitting.
- Freeze-thaw days drive ice dams on roofs and cracking in foundations and driveways.
- Heavy-rain days, an inch or more in 24 hours, are when basements flood, sump pumps run hardest and sewers back up.
- Muggy nights signal the humid summer air that keeps basements and crawl spaces damp enough for mold.
County-level detail
Every state links to its own Water Damage Risk Index, which ranks each county on the same factors, and every county page breaks down its own housing and weather. Use the state names in the table above, or choose your state.
Method and sources
Housing data comes from the U.S. Census Bureau's American Community Survey, ACS 2024 5-year estimates (2020-2024). Weather counts come from NOAA's nClimGrid-Daily county averages for 2015–2024. Full definitions are on our data sources and methodology page. You're welcome to cite these figures; please link to this page.