What is Norge soil and how does it affect Oklahoma foundations?

Reviewed by Preston, Oklahoma foundation repair consultant · Updated 2026-10-14

In short: Norge is a deep, well-drained soil on broad flats and upper slopes of old upland terraces in central Oklahoma. It has brown silt loam at the surface over a reddish silty clay loam subsoil. It is less clayey than neighboring soils like Kirkland and Renfrow, so drainage, leaks and fill deserve attention alongside any clay movement.

What is Norge soil?

Norge is an official USDA soil series classified as "Fine-silty, mixed, active, thermic Udic Paleustolls" ¹. "Fine-silty" is its particle-size family; in Norge the subsoil is silty clay loam throughout ¹. The soil formed in loamy alluvium of Pleistocene (Ice Age) age on paleoterraces, meaning old, high terraces left by ancient streams ¹.

Norge lies in the Central Rolling Red Prairies (MLRA 80A) and is rated as extensive ¹. The type location is in Pawnee County, about 8 miles northeast of Pawnee, and the series was established in Grady County in 1942 ¹. Mean annual precipitation is about 34 inches (range 30-42) ¹. Most areas have been farmed for small grains, sorghum, cotton and alfalfa ¹.

In Oklahoma, Norge areas fall in the OKC Metro and North-Central (Red Prairies and Wheat Belt) regions on Quaternary alluvium and terraces.

What does a Norge soil profile look like?

Source for the table: ¹. Other properties from the official description ¹:

• Drainage: well drained; permeability moderately slow ¹.
• Slopes: 0 to 8 percent; runoff low to high depending on slope ¹.
• Solum thickness: more than 60 inches. Depth to bedrock is not stated ¹.
• Subsoil: very hard and firm, with clay films on ped faces ¹.
• Carbonates: secondary carbonates deeper than 40 inches ¹.

What does Norge soil mean for foundations?

Shrink-swell

The USDA rates shrink-swell as linear extensibility, a linear expression of the volume change between moist soil and oven dryness: under 3 percent is low, 3 to 6 percent moderate, 6 to 9 percent high and 9 percent or more very high ³. The official description notes that Bethany, Kirkland and Renfrow have a finer, more clayey control section than Norge ¹. The rated value for a specific mapped unit is in Web Soil Survey ².

Clayey soils swell as they gain water and shrink as they dry, and uneven moisture change around a foundation is what drives damaging movement ⁴. See shrink-swell and the active zone.

Water around the house

Moderately slow permeability ¹ means water that soaks in near a foundation drains away gradually. The ASCE Geo-Institute guide lists roof runoff, grading, irrigation, trees and plumbing leaks as the moisture sources to control ⁴. It suggests:

• Discharging downspouts at least 3 feet from the foundation ⁴.
• Sloping soil away at least 3 inches in 5 feet ⁴.
• Keeping irrigation lines and heads at least 5 feet from the house ⁴.
• Watching water bills and repairing plumbing leaks ⁴.

See plumbing leaks under slab and surface drainage and grading.

Fill and erosion

Where a lot was built up or leveled with fill, see fill consolidation settlement. For how running water can remove soil from beneath footings, see erosion, undermining and washout voids.

How do you confirm the soil at a property?

Web Soil Survey shows the mapped soil unit for an address and lets users create custom reports ².

Related

• Kirkland soil
• Renfrow soil
• Pond Creek soil
• Bethany soil
• Soil series in the OKC metro