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Sinking foundation and house settling
A house settling a little in its first years is normal. A foundation that keeps sinking, with cracks wider than 1/8 inch, doors that bind and floors that slope, is moving, and the cause has to be found before anyone repairs it (HUD). On the 53 weekly Drought Monitor maps through October 13, 2026, 181 US counties with swelling clay under a third or more of their land spent, on average, over half their area in drought. They hold 5.6 million homes.
Normal settling and a problem
Almost every house has some foundation cracks, from concrete shrinking as it cures and from minor settling, usually 1/8 inch wide or less (Colorado Geological Survey). HUD's guide says settlement most often happens early in a building's life or after a dramatic change in conditions underground (HUD). It also says settlement is usually gradual, not a dramatic event, so there is time to find the cause before paying for a fix (HUD). Hairline cracks of 1/16 inch or less are usually cosmetic; cracks 1/8 inch and wider may reflect significant settlement (HUD).
A crack you can watch is a crack you can judge: measure it every month, and see which cracks matter and how each is repaired.
What settlement cracks look like
Fast settlement leaves cracks that taper, widest at one end and a hairline at the other, most often at corners and openings (HUD). Near-vertical cracks whose edges no longer line up, where a porch, bay window or addition meets the house, mean that part settled differently from the rest (HUD).
Why a foundation sinks
HUD lists the poor soils: highly expansive soil, organic or silty soil, and fill that was not compacted in layers (HUD). In Texas, large areas have clay that shrinks and swells with soil moisture, and that movement can shift a foundation (ASCE Texas Section). Trees or large shrubs near a foundation can shrink the soil under it, and removing them may stop the shrinking (ASCE Texas).
To check whether the ground under your house is the swelling kind, see how to tell if your house is on expansive clay. Drought is the other half. Clay under a slab gives up water in a dry year, and the table below shows where that has happened most. Foundation watering covers what cities allow while it lasts.
What fixes it
Start with an engineer: masonry problems call for a structural engineer, and a soils engineer as well when differential settlement looks like the cause (HUD). If movement continues and cracking is extensive, underpinning may be the only fix (HUD). Steel mini-piers are driven beside the footing to rock or firm soil, usually 15 to 25 feet down (HUD); helical piers screw a steel shaft into stable soil and can stabilize a settled foundation or raise it (HUD). Texas engineers caution that underpinning does not improve the parts of a foundation left without it, and that lifting a foundation on underpinning is unlikely to leave it level (ASCE Texas).
What it costs
Where guides price piers one at a time, a pier runs $1,000 to $3,000. Slab foundation repair, the work for a sinking slab, runs $350 to $20,000 a job across the guides below. Compare several: the spread is wide because the cause and the number of piers differ. For your city, use the foundation repair cost calculator; the full table is in foundation repair cost.
| Source | Where | Range | Average | Page updated |
|---|---|---|---|---|
| Angi | US | $350 to $20,000 | August 3, 2026 | |
| HomeGuide | US | $1,000 to $10,000 | February 6, 2026 | |
| Fixr | US | $1,000 to $10,000 | January 27, 2026 | |
| Today's Homeowner | US | $1,000 to $10,000 | April 9, 2025 | |
| Bob Vila | US | $350 to $20,000 | May 29, 2024 | |
| Angi | Houston, TX | $200 to $14,000 | October 10, 2025 | |
| Angi | Dallas, TX | $445 to $15,000 | October 7, 2025 | |
| Angi | Austin, TX | $3,000 to $8,500 | October 10, 2025 | |
| Angi | Columbus, OH | $1,000 to $10,000 | October 14, 2025 |
Where clay has been dry most of the past year
Counties with swelling clay (USDA SSURGO) on a third or more of their mapped land, ranked by homes. "In drought" is the average share of the county's area in drought (D1 or worse) across the last 53 weekly Drought Monitor maps to October 13, 2026. 181 of the 537 clay counties qualify, 70 of them in Texas. Rain is the last 12 months to August 2026 against the 1991-2020 normal (NOAA). Homes are from the Census ACS 2020-2024.
| County | Swelling clay | In drought, avg | Weeks half dry | Rain vs normal | Homes |
|---|---|---|---|---|---|
| Bexar County, TX | 51% | 82% | 41 of 53 | -7% | 820,780 |
| Travis County, TX | 39% | 94% | 53 of 53 | -20% | 618,236 |
| Fort Bend County, TX | 64% | 58% | 31 of 53 | -22% | 305,633 |
| Tulsa County, OK | 47% | 54% | 25 of 53 | -3% | 297,882 |
| Williamson County, TX | 60% | 69% | 39 of 53 | -11% | 262,644 |
| Guilford County, NC | 35% | 93% | 50 of 53 | -35% | 238,032 |
| Nueces County, TX | 56% | 79% | 42 of 53 | -11% | 154,408 |
| Durham County, NC | 43% | 96% | 51 of 53 | -34% | 153,022 |
| Brazoria County, TX | 64% | 59% | 32 of 53 | -16% | 150,321 |
| Lubbock County, TX | 42% | 75% | 41 of 53 | -41% | 139,344 |
| Jefferson County, TX | 56% | 59% | 31 of 53 | -20% | 109,884 |
| Montgomery County, AL | 53% | 67% | 36 of 53 | -23% | 106,121 |
Drought does not by itself mean a foundation is moving. The table shows where the soil conditions that move foundations have been present; a house's own footing, drainage and trees decide the rest. Look up your county or ZIP code in the soil by ZIP code lookup.
Written by Foundation Soils from the sources linked above and our soil data. Sources and methods.