Drainage that works.

Clay is slow

Most drainage problems around Tulsa start with the soil. OSU Extension notes that clay soils take in water slowly and crack in long dry spells. Its downspout guide explains that soils over 40% clay (hydrologic group D) absorb little water and shed most of it as runoff, so simply moving a downspout often isn't enough on clay.

Grade first

Oklahoma's residential code, now the 2024 IRC statewide, requires the ground to fall at least 6 inches in the first 10 feet away from the foundation, and hard surfaces within 10 feet to slope at least 2% away. Where a lot can't fit that, the code calls for swales or drains to carry the water off.

OSU warns against piling soil up the foundation to fix a low spot, because brick, insulation or studs behind raised soil stay wet. Regrading means moving the low point, not burying the house.

Downspouts

OSU's guide sets out where downspouts should drain: away from the foundation and the neighbors, at least 2 feet from a crawl space and 6 feet from basement walls, with no more than about 1,000 square feet of roof per downspout. The area receiving the water should slope 1 to 5% away from the house.

French drains and outlets

A true French drain is a trench of permeable rock that runs to the surface. A subsurface drain buries a perforated pipe in gravel below the surface. Both need an outlet: a pipe that daylights downhill, a dry well, or a sump pump where the yard is too flat for gravity. OSU also notes that soil works into every drain over time, so a good design leaves a way to clean it.

Tulsa's residential guidelines say a property can't block water flowing onto it from off-site, and must carry its own extra water to the street or another approved outlet where possible, without damaging the neighbors. The outlet is part of the design, not an afterthought.