What are foundation conditions like in McAlester, Oklahoma?

Reviewed by Preston · Updated 2026-11-12

In short: McAlester is clay country: about 53% of the city is mapped in soils rated high shrink-swell ¹. The soil survey also maps a water table within 2 feet of the surface at some point in the year under about 76% of it and bedrock within 40 inches under about 65% ¹. Which of these a house sits on decides whether clay swell, water, rock or soft ground is the thing to watch.

What does the soil survey show for McAlester?

McAlester covers about 18 square miles ² and had 18,171 people in the 2020 Census ².

Which soils matter most for houses in McAlester?

• Bengal, about 18% of the area ¹: Moderately deep, well drained, slowly permeable soils ³.
• Clebit, about 14% of the area ¹: Shallow, well drained, moderately rapidly permeable soils over hard sandstone that is tilted about 40 degrees from horizontal ⁴.
• Clearview, about 12% of the area ¹: Moderately deep, somewhat poorly drained, moderately slow permeable soils that formed in residuum weathered from acid sandstone with thin beds of clayey and sandy shales ⁵.
• Parsons, about 11% of the area ¹: Very deep, somewhat poorly drained soils that formed in clayey old alluvium or residuum weathered from fissile shales of Pennsylvanian age on interfluves, divides, and paleoterraces ⁶.
• Dennis, about 10% of the area ¹: Very deep, somewhat poorly drained soils that formed in residuum weathered from shale of Pennsylvanian age ⁷.

What does this mean for houses in McAlester?

Clay that swells and shrinks. Where high shrink-swell soil sits under a house, wet spells lift the slab edges and drought drops them, and uneven watering does more harm than uniform change. See perimeter wetting heave, edge drop in drought and tree-root drying.

Shallow water. A water table near the surface, often perched on tight clay or shale in winter and spring, keeps soil at slab edges and in crawl spaces wet and swollen. See groundwater and perched water, crawl space moisture and surface drainage and grading.

Shallow rock. Where bedrock is close to the surface, lots are often cut into rock on one side and built up with fill on the other, so fill settlement and slope creep matter more than clay swell, and piers can stop at very different depths across one house. See depth to rock from borings.

Which soils cover McAlester?

Looking for a foundation company near McAlester?

Companies that serve McAlester can appear on the company map in the Homeowner Hub. Paid listings there are marked Sponsored; the library and the AI guide don't rank or recommend any of them.

Buying or selling a house in McAlester? Realtors who serve the area can be on the same map, also marked Sponsored, and for realtors covers the seller disclosure form, inspections and the sale timeline. Seeing cracks at home? Start with for homeowners.

How were these numbers measured?

We overlaid the city limits from the Census Bureau ² on the USDA soil survey's map units ¹ and added up the area of each soil. Where a map unit is a mix of soils, its area was split by the percentages the survey lists for its major soils, so shares leave out minor inclusions and do not add to 100%. Shrink-swell is rated by the linear extensibility of a soil's most expansive layer, the survey's measure of how much it changes length between wet and dry (6% or more is high). Water table, bedrock and flooding come from the survey's map-unit summaries: the shallowest water table in any month, the shallowest bedrock, and the most common flooding frequency. Bedrock here includes soft, weathered sandstone and shale that a pier can push through, so it is not the depth where piers stop. These are mapped averages, not a test of any one lot; fill, grading and the soil actually under a house can differ, which is why a site visit or soil boring still decides a repair.

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