Richardson, Texas

Inside Richardson's city limits, shrink-swell clay limits houses without basements on 52% of mapped land, higher than 59% of Texas cities. A shallow water table limits basements on under 1%.

That clay share is close to Dallas County's 51%. FEMA's flood data list 6 flood losses since 2016 in the 3 ZIP codes overlapping the city. Of its 47,960 homes, 44% were built before 1980; the median dates from 1986.

Data as of September 22, 2026 · sources · in Dallas County

52%

expansive clay: shrink-swell limits slab homes

<1%

high water table: limits basements

flood losses since 2016 in 3 overlapping ZIPs

44%

of homes built before 1980

Soil under Richardson city limits

Expansive clay (limits slab homes)	52.0%
High water table (limits basements)	0.1%
Septic fields very limited	85.0%
Clay swell (LEP, by area)	10.4%
High-swell land (LEP 6%+)	50.2%
Urban land, not rated	19.8%
Mapped soil	18,353 acres

Soil series	Share here	Series nationally: expansive clay
Houston Black	36%	91%
Austin	18%	93%
Eddy	4%	0%
Heiden	3%	80%
Lewisville	3%	n/a
Stephen	2%	n/a

Richardson city limits inside Dallas County, shaded by the city's expansive clay share.under 10%10-25%25-40%40-60%60%+

How we count

What the numbers mean here

Clay swell averages a linear extensibility of 10.4% by land area here, and 50% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 52% of the mapped land.

Clay shrinks as it dries: 100% of Dallas County is in drought on the latest map, and 52% of Richardson's mapped land has shrink-swell clay.

USDA rates 85% of the land very limited for septic absorption fields.

Drought in Dallas County

100% of Dallas County is in drought (D1 or worse) on the September 22, 2026 map. County detail.

September 30, 2025Share of area in drought, weeklySeptember 22, 2026

Flood losses by ZIP code

FEMA flood records since 2016 in the ZIP codes that overlap Richardson. ZIP areas reach past city limits.

ZIP	Share of city land	Flood losses	Paid
75080	40%	3	$28,753
75081	31%	0	$0
75082	29%	3	$39,039

Homes in Richardson

Housing units	47,960
Median year built	1986
Built before 1980	44%
Built 2000 or later	31%
Owner-occupied	51%
Median value, owner-occupied	$431,400
Single-family detached	54%

Nearby cities

Place	Distance	Expansive clay	High water table
Plano	6 mi	75%	under 1%
Garland	6 mi	59%	under 1%
Murphy	7 mi	80%	under 1%
Addison	7 mi	28%	under 1%
Sachse	7 mi	81%	under 1%
Parker	8 mi	69%	under 1%
Allen	10 mi	78%	under 1%
University Park	10 mi	33%	0%

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