Johnston County, OK Shrink-Swell Risk

Shrink-swell potential in Johnston County, OK

Moderate

Soil across 42.6% of Johnston County, OK comes back "Moderate" in USDA's shrink-swell data, averaging 4.05% linear extensibility. Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Johnston County, OK - never a reading for one specific parcel. A site-specific soil report, usually $1,000-$5,000, is what an engineer would actually pull before designing a foundation on a lot in Johnston County.

Johnston County: the real numbers

Johnston 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 Johnston County, OK compares

Among the 3,085 rated counties on this site, Johnston County, OK ranks 542 most-constrained nationally, and 20 of 77 within Oklahoma. Johnston County covers 643 square miles and counts 10,293 residents.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Bradford County, FL and Sanpete County, UT 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 Oklahoma

Every county in Oklahoma is on this site, including McCurtain County, OK and McClain County, OK. The full underlying dataset is downloadable directly, one row per county.