Summit County, Colorado
USDA's soil survey flags shrink-swell clay on 4% of Summit County's mapped land and a shallow water table under basements on 5%, both below the national shares of 15% and 29%. The soil survey maps 28% of the county's land area; these shares describe the mapped part.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 5 flood losses here since 2016. 31% of homes were built before 1980, against 50% nationally; the median home dates from 1989.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Summit County
| Expansive clay (limits slab homes) | 3.9% |
| High water table (limits basements) | 5.1% |
| Septic fields very limited | 74.6% |
| Clay swell (LEP, by area) | 2.3% |
| High-swell land (LEP 6%+) | 3.9% |
| Mapped soil | 108,700 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Frisco | 17% | n/a |
| Grenadier | 10% | n/a |
| Peeler | 9% | n/a |
| Youga | 6% | n/a |
| Quander | 5% | n/a |
| Anvik | 4% | n/a |
How we count · survey areas CO690 (2025-08-29)
What the numbers mean here
Rain over the 12 months to August 2026: 18.71 in, 7.12 in below the 1991-2020 average year of 25.83 in.
USDA rates 75% of the land very limited for septic absorption fields.
With shrink-swell clay on 4% and a shallow water table on 5% of the land, the soil survey points to neither problem across most of Summit County; conditions still vary lot by lot.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 52 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 100% |
| D3 extreme or worse | 100% |
| D4 exceptional | 87.9% |
Flood losses since 2016
5 flood losses since 2016, $4,585 paid. The worst year was 2025, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 1 |
| 2018 | 0 |
| 2019 | 1 |
| 2020 | 1 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 1 |
| 2024 | 0 |
| 2025 | 1 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 25.83 in |
| 12 months to August 2026 | 18.71 in (-7.12) |
| 2025 | 20.87 in (-4.96) |
| Wettest year since 1895 | 1945: 39.42 in |
| Driest year since 1895 | 1910: 16.32 in |
| Days with 1 inch or more, normal at DILLON 1 E (5 mi away) | 0 |
Homes
| Housing units | 32,251 |
| Median year built | 1989 |
| Built before 1980 | 31% |
| Built 2000 or later | 24% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $939,900 |
| Single-family detached | 35% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Clear Creek County, CO | 25 mi | 0% | 3% |
| Eagle County, CO | 30 mi | 4% | 1% |
| Lake County, CO | 31 mi | 0% | 15% |
| Grand County, CO | 34 mi | 5% | 6% |
| Gilpin County, CO | 36 mi | 0% | 3% |
| Park County, CO | 41 mi | 2% | 7% |
| Jefferson County, CO | 47 mi | 17% | 2% |
| Pitkin County, CO | 50 mi | n/a | n/a |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status