Jerome County, Idaho
USDA's soil survey flags shrink-swell clay on under 1% of Jerome County's mapped land and a shallow water table under basements on under 1%, both below the national shares of 15% and 29%. 100% of the county is in drought on the October 13, 2026 Drought Monitor map.
FEMA's flood data list no flood losses here since 2016. 47% of homes were built before 1980, against 50% nationally; the median home dates from 1983.
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 Jerome County
| Expansive clay (limits slab homes) | under 0.1% |
| High water table (limits basements) | under 0.1% |
| Septic fields very limited | 75.6% |
| Clay swell (LEP, by area) | 3.0% |
| High-swell land (LEP 6%+) | 3.7% |
| Mapped soil | 387,300 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Power | 14% | n/a |
| Portneuf | 9% | n/a |
| Sluka | 8% | n/a |
| Banbury | 7% | n/a |
| Paulville | 6% | n/a |
| Bahem | 5% | n/a |
How we count · survey areas ID704 (2025-08-27)
What the numbers mean here
Rain over the 12 months to August 2026: 7.06 in, 2.95 in below the 1991-2020 average year of 10.01 in.
USDA rates 76% of the land very limited for septic absorption fields.
With shrink-swell clay on under 1% and a shallow water table on under 1% of the land, the soil survey points to neither problem across most of Jerome 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 | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Jerome County since 2016.
Rain
| Average year, 1991-2020 | 10.01 in |
| 12 months to August 2026 | 7.06 in (-2.95) |
| 2025 | 7.71 in (-2.30) |
| Wettest year since 1895 | 1907: 17.96 in |
| Driest year since 1895 | 2013: 4.38 in |
| Days with 1 inch or more, normal at HAZELTON (9 mi away) | 0.3 |
Homes
| Housing units | 8,810 |
| Median year built | 1983 |
| Built before 1980 | 47% |
| Built 2000 or later | 31% |
| Owner-occupied | 75% |
| Median value, owner-occupied | $271,800 |
| Single-family detached | 83% |
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 |
|---|---|---|---|
| Lincoln County, ID | 21 mi | 16% | 1% |
| Twin Falls County, ID | 31 mi | 13% | 1% |
| Minidoka County, ID | 34 mi | 1% | 7% |
| Gooding County, ID | 34 mi | 26% | under 1% |
| Cassia County, ID | 43 mi | 3% | 2% |
| Blaine County, ID | 51 mi | 11% | 4% |
| Camas County, ID | 62 mi | 19% | 22% |
| Power County, ID | 72 mi | 1% | 2% |
Sources: USDA SSURGO (August 27, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status