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Foundation watering

Foundation Soils · updated September 28, 2026

Clay under a slab shrinks as it dries and swells as it wets, so Texas engineers advise keeping soil moisture near uniform on all sides of the foundation, and warn against watering too much (ASCE Texas Section). On the September 22, 2026 Drought Monitor map, 243 counties with shrink-swell clay on at least a third of their mapped land were at least half in drought, 93 of them in Texas.

How to water

Houston's Foundation Performance Association says to water at least one to two feet from the foundation, lightly, so tree roots aren't drawn toward it; to keep sprinklers from spraying the structure; and, when dry soil cracks and pulls away from the foundation, not to water straight into the gap (Foundation Performance Association). Its advice on timing: keep the system on manual and water in dry periods, when the lawn starts to wilt (FPA).

What Texas cities allow in drought

Not everywhere

The Colorado Geological Survey's advice for swelling soils runs the other way: poorly planned lawn and shrub watering is "the direct cause of much of the damage" to houses on those soils, and it advises keeping sprinklers about 5 feet from the foundation (Colorado Geological Survey).

Clay counties in drought this week

Counties with shrink-swell clay on at least a third of their land and at least half their area in drought (D1 or worse), ranked by both together. Updated with each weekly map.

CountyExpansive clayIn drought, September 22, 2026
Haakon County, SD89%98.7%
Swisher County, TX87%100%
Humphreys County, MS86%100%
Floyd County, TX84%100%
Hale County, TX83%100%
Castro County, TX82%100%
Sharkey County, MS79%100%
Hunt County, TX78%100%
Delta County, TX77%100%
Sunflower County, MS76%100%
Labette County, KS75%100%
Navarro County, TX75%100%
Tensas Parish, LA75%100%
Kaufman County, TX73%100%
Collin County, TX72%100%

Written by Foundation Soils from the sources linked above and our county data. Sources and methods.