Expansive Soil in Imperial County, CA
Does Imperial County, CA have expansive soil? Yes: the dominant shrink-swell rating for Imperial County, CA is High, with 81% of the county's mapped soil acres in the High class.
Soil class breakdown for Imperial County
What a High rating means for a slab foundation
Soils in this class change volume significantly between wet and dry conditions. Seasonal movement can flex a slab enough to open drywall cracks, stick doors and windows, and separate brick veneer. Foundation repair in high-rated counties commonly involves piers that carry the structure past the active clay layer, along with drainage and moisture management.
This is a county-level rating built from USDA soil survey data, not a parcel-level geotechnical assessment. Soils change from lot to lot; a geotechnical engineer or foundation professional can assess the ground under your specific property.
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Methodology and sources
This rating is computed from USDA NRCS SSURGO soil survey data
:
for each soil component we take the maximum linear extensibility percent
(lep_r) among horizons starting within 0 to 100 cm of the surface, apply the
NRCS National Soil Survey Handbook Part 618 class limits (Low under 3 percent, Moderate 3
to under 6, High 6 to under 9, Very High 9 and above), assign each map unit the class
holding the plurality of component percent, and sum map unit acres per class across the
county, excluding unmapped and water areas.
- Data source: USDA NRCS SSURGO via Soil Data Access
- Class limits: NRCS National Soil Survey Handbook, Part 618
- Survey coverage: 94% of county map acres
- Computed: 2026-07-05
- Note: max lep_r over horizons with hzdept_r<100cm (major components only), comppct_r plurality per mapunit, county rollup by muaoverlap.areaovacres, class limits NSSH Part 618, shares are fractions of rated acres
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FAQ
Does Imperial County, CA have expansive soil?
Yes: the dominant shrink-swell rating for Imperial County, CA is High, with 81% of the county's mapped soil acres in the High class.
What does a High rating mean for a slab foundation?
Soils in this class change volume significantly between wet and dry conditions. Seasonal movement can flex a slab enough to open drywall cracks, stick doors and windows, and separate brick veneer. Foundation repair in high-rated counties commonly involves piers that carry the structure past the active clay layer, along with drainage and moisture management.
Is this a parcel-level soil report?
No. This is a county-level rollup of USDA NRCS SSURGO soil survey data for Imperial County, CA. Soils vary lot to lot, so a geotechnical engineer or foundation professional should assess your specific property before you make repair decisions.
How much does foundation repair cost near Imperial County?
Pricing depends on the repair method and how far the movement has progressed, from sealing a single crack to installing piers. SlabLocal publishes city-level foundation repair cost guides with sourced ranges for cities across California.