Houston, Texas

Inside Houston's city limits, shrink-swell clay limits houses without basements on 29% of mapped land. A shallow water table limits basements on 48%.

That clay share is close to Harris County's 25%. USDA doesn't rate the 26% of mapped land classed as urban land, so these shares are floors. FEMA's flood data list 46,975 flood losses since 2016 in the 90 ZIP codes overlapping the city. Of its 1,040,576 homes, 47% were built before 1980; the median dates from 1982.

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

29%

expansive clay: shrink-swell limits slab homes

48%

high water table: limits basements

46,975

flood losses since 2016 in 90 overlapping ZIPs

47%

of homes built before 1980

Soil under Houston city limits

Expansive clay (limits slab homes)	28.6%
High water table (limits basements)	47.9%
Septic fields very limited	73.5%
Clay swell (LEP, by area)	6.3%
High-swell land (LEP 6%+)	30.3%
Urban land, not rated	25.6%
Mapped soil	430,973 acres

Soil series	Share here	Series nationally: expansive clay
Lake Charles	14%	97%
Bernard	12%	43%
Clodine	7%	n/a
Addicks	4%	n/a
Katy	3%	0%
Gessner	3%	n/a

Houston city limits inside Harris 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 6.3% by land area here, and 30% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 29% of the mapped land.

Clay shrinks as it dries: 16.5% of Harris County is in drought on the latest map, and 29% of Houston's mapped land has shrink-swell clay.

On 48% of Houston's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.

USDA rates 74% of the land very limited for septic absorption fields.

Drought in Harris County

16.5% of Harris 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 Houston. ZIP areas reach past city limits.

ZIP	Share of city land	Flood losses	Paid
77032	3%	495	$25.6 million
77077	3%	866	$93.9 million
77084	3%	2,308	$252.9 million
77339	2%	1,882	$295.2 million
77034	2%	1,182	$81.3 million
77043	2%	242	$8.5 million
77048	2%	97	$2.7 million
77075	2%	546	$44.8 million
77045	2%	179	$4.3 million
77013	2%	462	$45.6 million
77017	2%	166	$11.0 million
77082	2%	308	$2.6 million
77016	1%	532	$19.9 million
77028	1%	448	$34.2 million
77029	1%	268	$21.6 million
77088	1%	1,281	$74.1 million
77092	1%	377	$23.2 million
77345	1%	776	$166.1 million
77007	1%	328	$24.5 million
77015	1%	533	$48.2 million
77020	1%	92	$4.8 million
77047	1%	246	$8.2 million
77051	1%	59	$838,407
77061	1%	172	$12.3 million
77078	1%	401	$27.5 million
77079	1%	1,975	$402.7 million
77093	1%	866	$35.6 million
77338	1%	508	$71.6 million
77450	1%	1,221	$185.0 million
77018	1%	422	$32.2 million
77036	1%	116	$3.0 million
77041	1%	640	$72.9 million
77055	1%	204	$5.6 million
77059	1%	223	$19.1 million
77072	1%	617	$7.6 million
77089	1%	2,318	$189.0 million
77091	1%	422	$23.3 million
77396	1%	265	$11.8 million
77008	1%	816	$45.1 million
77009	1%	348	$21.9 million
77024	1%	1,116	$143.0 million
77026	1%	509	$22.2 million
77042	1%	624	$93.3 million
77080	1%	565	$20.4 million
77087	1%	192	$6.0 million
77021	1%	245	$10.2 million
77022	1%	589	$26.0 million
77023	1%	69	$2.9 million
77033	1%	229	$4.5 million
77035	1%	936	$102.8 million
77062	1%	346	$18.1 million
77074	1%	1,609	$128.9 million
77085	1%	38	$402,113
77096	1%	3,052	$456.7 million
77099	1%	446	$12.8 million
77004	1%	273	$10.2 million
77040	1%	982	$45.6 million
77054	1%	46	$2.0 million
77025	1%	1,444	$172.7 million
77053	1%	102	$2.9 million
77057	1%	200	$17.2 million
77060	1%	780	$87.0 million
77063	1%	476	$47.4 million
77076	1%	253	$8.5 million
77489	1%	135	$1.8 million
77598	1%	236	$17.5 million
77012	1%	58	$3.9 million
77019	1%	119	$16.1 million
77058	1%	371	$18.4 million
77064	1%	150	$6.0 million
77071	1%	350	$15.8 million
77011	1%	36	$2.9 million
77056	1%	368	$41.5 million
77070	1%	1,236	$184.2 million
77081	1%	141	$4.8 million
77003	under 1%	12	$108,515
77006	under 1%	78	$890,829
77027	under 1%	94	$11.6 million
77030	under 1%	187	$12.1 million
77031	under 1%	131	$10.3 million
77090	under 1%	639	$96.9 million
77002	under 1%	81	$11.8 million
77005	under 1%	248	$10.0 million
77037	under 1%	1,680	$88.3 million
77067	under 1%	75	$924,829
77098	under 1%	59	$1.9 million
77094	under 1%	152	$16.7 million
77204	under 1%	0	$0
77010	0%	0	$0
77046	0%	11	$231,598

Homes in Houston

Housing units	1,040,576
Median year built	1982
Built before 1980	47%
Built 2000 or later	30%
Owner-occupied	42%
Median value, owner-occupied	$277,800
Single-family detached	43%

What repairs cost

Published ranges from cost guides, not quotes. More sources, and where they disagree.

Work	Range	Source
Foundation repair, Houston	$3,276 to $6,729	Angi, October 10, 2025
Pier-and-beam repair, Houston	$990 to $15,500	Angi, October 10, 2025

Nearby cities

Place	Distance	Expansive clay	High water table
West University Place	5 mi	56%	48%
Hilshire Village	6 mi	27%	56%
Southside Place	6 mi	63%	57%
Hunters Creek Village	7 mi	24%	49%
Spring Valley Village	7 mi	0%	56%
Bellaire	7 mi	56%	28%
Hedwig Village	8 mi	0%	55%
Piney Point Village	8 mi	20%	54%

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