What are foundation and soil conditions in ZIP code 74120 (Tulsa)?

Reviewed by Preston · Updated 2026-11-12

In short: Most of ZIP code 74120, about 61%, is mapped as urban land: ground covered by buildings and pavement that the soil survey does not classify ¹. So the map says little about the soil under a given house here; the soils mapped in the rest point to what is likely underneath, and a soil boring settles it.

What does the soil survey show for 74120?

ZIP code 74120 covers about 2 square miles of land and had 5,037 people in the 2020 Census ²; its center falls in Tulsa.

Which soils matter most for houses in 74120?

• Dennis, about 17% of the area ¹: Very deep, somewhat poorly drained soils that formed in residuum weathered from shale of Pennsylvanian age ³.
• Kamie, about 16% of the area ¹: Very deep, well drained soils that formed in material weathered from predominantly loamy alluvium of Pleistocene age ⁴.
• Urban land, about 61%, is ground the survey maps as covered by buildings and pavement rather than classifying its soil ¹.

What does this mean for houses in 74120?

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.

Which soils cover 74120?

Looking for a foundation company near ZIP code 74120?

Companies that serve ZIP code 74120 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 74120? 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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• Shrink-swell and the active zone