Why Do Foundations Crack in Johnson County?
Johnson County has the most weeks of extreme drought of the seven, on soil where the middle class is nearly empty.
Foundations crack in Johnson County because 59.6% of the rated soil, by acre, is high or very high shrink-swell clay, and the county has had long dry spells to shrink it. HGS Engineering, PLLC (Texas Firm #21268) found 27 weeks since 2021 in which half or more of Johnson County was in extreme drought or worse, the highest count of the seven counties.
Reviewed by Heath Salmon, PE, October 16, 2026. Soil data downloaded 2026-10-16, drought data downloaded 2026-10-16.
What Does the Soil Survey Say About Johnson County?
The mix of classes is 34.1% low, 6.3% moderate, 37.7% high and 21.9% very high. The moderate class is unusually small, only 6.3% of rated acres, which means the ground is mostly either quiet or active, with little in between. A house in Johnson County is either on soil that barely moves or on soil that moves a lot.
Only 14.2% of the county is unrated, the lowest unrated share of the seven. That makes the table more representative of what is actually under a Johnson County house than it is for Dallas or Tarrant County, where urban land covers a quarter or more of the map.
Cleburne is the county seat and the firm has a page for it. The inspection area includes the whole county and the firm answers requests by email, as it does for every other county on this site.
| Class | Rated acres | Share of rated acres |
|---|---|---|
| Low | 137,362 | 34.1% |
| Moderate | 25,564 | 6.3% |
| High | 151,977 | 37.7% |
| Very high | 88,060 | 21.9% |
| High plus very high | 240,037 | 59.6% |
| Not rated (urban land, water, pits) | 66,662 | 14.2% of all acres |
| Rank among the seven counties, high plus very high | 5 of 7 | |
Which Johnson County Soils Carry the High Ratings?
Crosstell accounts for 59,554 acres of high or very high rating, then Heiden (53,841), Sanger (37,196), Ponder (18,840) and Slidell (13,492). Johnson is the only county of the seven where Crosstell is the top soil by high-rated acreage, and two or three soil names account for most of its active ground.
The survey lists 216 components in Johnson County. The table sums the acres of every component that shares a name.
| Soil name | High or very high acres |
|---|---|
| Crosstell | 59,554 |
| Heiden | 53,841 |
| Sanger | 37,196 |
| Ponder | 18,840 |
| Slidell | 13,492 |
How Dry Has Johnson County Been Since 2021?
Johnson County had land in D2 or worse in 70 of 262 weeks from 2021-10-12 to 2026-10-13. Half or more of the county was in D2 or worse for 50 weeks and in D3 or worse for 27 weeks. The 2022 count of weeks with any D2 was 47, the highest single-year count in the county, followed by 15 in 2023.
The latest map, dated 2026-10-13, puts 4.38% of the county in D2 or worse. After a dry run that long, a clay soil has opened cracks that the next rain fills before it swells back, and the foundation has to take the difference.
| Weeks counted | 262 |
|---|---|
| Weeks with any land in D2 (severe) or worse | 70 |
| Weeks with half or more of the county in D2 or worse | 50 |
| Weeks with half or more in D3 (extreme) or worse | 27 |
| Mean share of the county in D2 or worse | 19.2% |
| Latest week (2026-10-13): in D2 or worse, in D3 or worse | 4.38% and 0% |
| Weeks with any D2 in 2021 | 1 |
| Weeks with any D2 in 2022 | 47 |
| Weeks with any D2 in 2023 | 15 |
| Weeks with any D2 in 2024 | 0 |
| Weeks with any D2 in 2025 | 1 |
| Weeks with any D2 in 2026 | 6 |
What Does an Inspection Do With This Information?
The report covers conditions observed, permitting requirements for any indicated repair, and drainage recommendations. In a county where the soil is strongly active, the drainage section carries most of the practical weight, because water management at the wall is what a homeowner can change.
Because the firm does not repair foundations, the report sets out the findings and leaves the choice of contractor to the owner.
See the foundation inspection service page or use the request form.
How Were These Numbers Made?
Method: for each soil component in the Johnson County SSURGO survey, the script averages linear extensibility over the top 100 centimeters, weighted by horizon depth. The average puts the component in an NRCS class: low under 3 percent, moderate 3 to under 6, high 6 to under 9, very high 9 or more. Acres are the map unit's acres times the component's percent of the unit, and components with no reading are left out of the percentages. The Drought Monitor figures are weekly county statistics. Both raw pulls are committed with the scripts, and a gate re-runs them before each build. A soil survey describes a county, never a single lot.
Where Does the Firm Work in Johnson County?
- Foundation inspection in Cleburne, TX
- Foundation inspection service
- Other counties: Tarrant, Dallas, Ellis, Parker, Denton, Collin
Frequently Asked Questions
Why do foundations crack in Johnson County?
Because 59.6% of the rated soil is high or very high shrink-swell clay, and the county has been through repeated dry periods. Water reaching the slab unevenly moves it unevenly.
How much of Johnson County is in extreme drought?
The Drought Monitor map dated 2026-10-13 shows 0% in D3 or worse and 4.38% in D2 or worse. Across the period since 2021 there were 27 weeks with half or more of the county in D3 or worse.
Does the firm cover Cleburne?
Yes. The firm has a page for Cleburne, in Johnson County, and takes requests by email for the rest of the county.
Where is the data from?
USDA NRCS Soil Data Access for SSURGO, pulled 2026-10-16, and the U.S. Drought Monitor, pulled 2026-10-16. Both raw files are committed and the page numbers are recomputed from them.
Sources
- USDA Natural Resources Conservation Service, Soil Data Access web service (SSURGO tabular data)Linear extensibility (lep_r), map unit acres and component percent for the seven counties, queried on 2026-10-16.
- National Drought Mitigation Center, University of Nebraska-Lincoln, U.S. Drought Monitor data services, county statisticsWeekly percent of each county in D2 (severe) or worse and D3 (extreme) or worse, October 2021 to October 2026.
- Texas Board of Professional Engineers and Land Surveyors, Engineering Firm RegistrationThe firm registration number and the licensed engineer seal.
- Texas Section, American Society of Civil Engineers, Guidelines for the Evaluation and Repair of Residential Foundations, Version 3Foundation evaluation practice, drainage away from the foundation and North Texas soil movement.
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