What are foundation and soil conditions in ZIP code 74146 (Tulsa)?

Reviewed by Preston · Updated 2026-11-12

In short: ZIP code 74146 is clay country: about 72% of the area 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 88% of it and occasional or frequent flooding on about 12% ¹.

What does the soil survey show for 74146?

ZIP code 74146 covers about 5 square miles of land and had 16,427 people in the 2020 Census ²; its center falls in Tulsa.

Which soils matter most for houses in 74146?

• Okemah, about 34% of the area ¹: Very deep, somewhat poorly drained soils that formed in material weathered from loamy and clayey alluvium or colluvium from shale of Pennsylvanian age ³.
• Parsons, about 20% 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 ⁴.
• Pharoah, about 14% of the area ¹: Very deep somewhat poorly drained soils that were formed in fine textured residuum, on the uplands in the Cherokee Prairies ⁵.
• Dennis, about 13% of the area ¹: Very deep, somewhat poorly drained soils that formed in residuum weathered from shale of Pennsylvanian age ⁶.
• Radley, about 10% of the area ¹: Very deep, moderately well drained soils that formed in stratified silty alluvium ⁷.

What does this mean for houses in 74146?

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.

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 74146?

Looking for a foundation company near ZIP code 74146?

Companies that serve ZIP code 74146 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 ZIP code 74146? 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 ZIP code tabulation area (the Census approximation of a ZIP code) 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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• ZIP code 74145
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• Shrink-swell and the active zone