What are foundation conditions like in Seminole, Oklahoma?

Reviewed by Preston · Updated 2026-11-12

In short: About 29% of Seminole is mapped in soils rated high shrink-swell and 8% moderate ¹. The soil survey also maps a water table within 2 feet of the surface at some point in the year under about 53% of it, bedrock within 40 inches under about 47% and occasional or frequent flooding on about 15% 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 Seminole?

Seminole covers about 14 square miles ² and had 7,146 people in the 2020 Census ².

Which soils matter most for houses in Seminole?

• Seminole, about 19% of the area ¹: Deep, moderately well drained, slowly permeable soils that formed in clayey sediments or material weathered from shale of Permian age ³.
• Stephenville, about 18% of the area ¹: Moderately deep, well drained, soils formed in material weathered from sandstone of Permian age ⁴.
• Darnell, about 11% of the area ¹: Shallow, well drained to somewhat excessively drained soils formed in material weathered from sandstone of Permian age ⁵.
• Niotaze, about 7% of the area ¹: Moderately deep, somewhat poorly drained, slowly permeable soils that formed in residuum from weathered shale and colluvium from sandstone of Pennsylvanian age ⁶.
• Chickasha, about 6% of the area ¹: Deep, well drained, moderately permeable soils that formed in material weathered from sandstone of Permian age ⁷.
• Water, about 4%, is open water ¹.

What does this mean for houses in Seminole?

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.

Flood-prone soils. Floodplain soils are layered stream deposits: softer, wetter and more variable than upland soils, and they flood. See soft soil consolidation and Quaternary alluvium and terraces.

Which soils cover Seminole?

Looking for a foundation company near Seminole?

Companies that serve Seminole 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 Seminole? 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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