Johnson County, IA Shrink-Swell Risk

Johnson County's SSURGO shrink-swell reading

Moderate

In Johnson County, IA, 79% of the surveyed soil carries a "Moderate" shrink-swell rating, 3.79% linear extensibility on average. Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.

Before you rely on this for one address

Johnson County's reading is an average across the whole county, not a promise about any one lot inside it. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Johnson County will actually do.

Budgeting for Johnson County, IA

Johnson County's soil reading points toward standard foundation practice as the likely outcome, not the exception. A geotechnical report runs $1,000-$5,000, typically around $2,700. Foundation repair, if a specific lot turns out to differ from the county average, runs $5,000-$15,000.

How Johnson County, IA compares

Among the 3,085 rated counties on this site, Johnson County, IA ranks 679 most-constrained nationally, and 52 of 99 within Iowa. The county spans 613 square miles, home to 160,080 people.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Todd County, MN and Storey County, NV are worth a look for comparison.

How this reading is built, and its real limits · Moisture management: the cheap fix that works on any soil

Elsewhere in Iowa

Every county in Iowa is on this site, including Shelby County, IA and Boone County, IA. The full underlying dataset is downloadable directly, one row per county.