Dallas County, IA Shrink-Swell Risk

Shrink-swell potential in Dallas County, IA

Low

Soil across 68.2% of Dallas County, IA comes back "Low" in USDA's shrink-swell data, averaging 2.98% linear extensibility. That's the easiest starting point on this site's scale - a standard foundation is the reasonable default here, though any one lot can still differ.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Dallas County, IA - never a reading for one specific parcel. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Dallas County will actually do.

Dallas County: the real numbers

Dallas 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.

Dallas County's rank among Iowa counties

Among the 3,085 rated counties on this site, Dallas County, IA ranks 1,206 most-constrained nationally, and 86 of 99 within Iowa. Dallas County, IA is 588 square miles with a population of 115,343.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Rockbridge County, VA and La Paz County, AZ 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 Monroe County, IA and Louisa County, IA. The full underlying dataset is downloadable directly, one row per county.