What are foundation conditions like in Sulphur, Oklahoma?

Reviewed by Preston · Updated 2026-11-12

In short: About 36% of Sulphur is mapped in soils rated high shrink-swell and 44% moderate ¹. The soil survey also maps bedrock within 40 inches under about 35% 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 Sulphur?

Sulphur covers about 7 square miles ² and had 5,065 people in the 2020 Census ².

Which soils matter most for houses in Sulphur?

• Rayford, about 30% of the area ¹: Shallow, well drained, moderately permeable prairie soils that formed in material weathered from limestone conglomerate of Pennsylvanian age ³.
• Clarita, about 21% of the area ¹: Very deep, moderately well drained, very slowly permeable upland soils ⁴.
• Durant, about 11% of the area ¹: Very deep, moderately well drained, very slowly permeable soils that formed in clayey residuum weathered from clayey deposits and shales of Cretaceous age ⁵.
• Chigley, about 8% of the area ¹: Very deep, moderately well drained, moderately slowly permeable upland soils that formed in material weathered from conglomerate rock of Pennsylvanian age ⁶.
• Garvin, about 4% of the area ¹: Deep, moderately well drained, very slowly permeable soils ⁷.
• Urban land, about 9%, is ground the survey maps as covered by buildings and pavement rather than classifying its soil ¹.

What does this mean for houses in Sulphur?

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 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 Sulphur?

Looking for a foundation company near Sulphur?

Companies that serve Sulphur 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 Sulphur? 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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