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McKinney, Texas
Inside McKinney's city limits, shrink-swell clay limits houses without basements on 73% of mapped land, higher than 77% of Texas cities. A shallow water table limits basements on under 1%.
That clay share is close to Collin County's 72%. FEMA's flood data list 12 flood losses since 2016 in the 4 ZIP codes overlapping the city. Of its 77,617 homes, 8% were built before 1980; the median dates from 2007.
Data as of September 22, 2026 · sources · in Collin County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 4 overlapping ZIPs
of homes built before 1980
Soil under McKinney city limits
| Expansive clay (limits slab homes) | 73.0% |
| High water table (limits basements) | 0.4% |
| Septic fields very limited | 83.9% |
| Clay swell (LEP, by area) | 8.8% |
| High-swell land (LEP 6%+) | 51.1% |
| Mapped soil | 44,423 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Houston Black | 40% | 91% |
| Austin | 22% | 93% |
| Altoga | 8% | n/a |
| Tinn | 7% | n/a |
| Heiden | 6% | 80% |
| Lewisville | 5% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 8.8% by land area here, and 51% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 73% of the mapped land.
Clay shrinks as it dries: 100% of Collin County is in drought on the latest map, and 73% of McKinney's mapped land has shrink-swell clay.
USDA rates 84% of the land very limited for septic absorption fields.
Drought in Collin County
100% of Collin County is in drought (D1 or worse) on the September 22, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap McKinney. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 75071 | 41% | 0 | $0 |
| 75069 | 24% | 7 | $153,863 |
| 75072 | 18% | 4 | $21,176 |
| 75070 | 17% | 1 | $0 |
Homes in McKinney
| Housing units | 77,617 |
| Median year built | 2007 |
| Built before 1980 | 8% |
| Built 2000 or later | 73% |
| Owner-occupied | 64% |
| Median value, owner-occupied | $471,800 |
| Single-family detached | 71% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Fairview | 5 mi | 71% | 1% |
| New Hope | 6 mi | 49% | under 1% |
| Allen | 7 mi | 78% | under 1% |
| Lowry Crossing | 7 mi | 72% | under 1% |
| Lucas | 8 mi | 76% | under 1% |
| Melissa | 9 mi | 69% | under 1% |
| Prosper | 9 mi | 77% | under 1% |
| Weston | 9 mi | 77% | under 1% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (September 22, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status