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Iowa Colony, Texas
Inside Iowa Colony's city limits, shrink-swell clay limits houses without basements on 76% of mapped land, the 3rd-highest of 24 cities in Brazoria County. A shallow water table limits basements on 28%.
That clay share is above Brazoria County's 64%. FEMA's flood data list 403 flood losses since 2016 in ZIP code 77583 overlapping the city. Of its 4,683 homes, 2% were built before 1980; the median dates from 2015.
Data as of October 13, 2026 · sources · in Brazoria County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Foundation repair in Iowa Colony
Foundation repair in Iowa Colony: shrink-swell clay limits slab homes on 76% of Iowa Colony's mapped land, more than in 81% of Texas cities.
About 4,400 of Iowa Colony's 4,683 homes are detached houses.
| Who designs the repair | The ASCE Texas Section's repair guidelines say a Texas-licensed engineer should evaluate the foundation and design the repair (2022 guidelines) |
| Prices | Cost guide ranges compared |
Soil under Iowa Colony city limits
| Expansive clay (limits slab homes) | 76.4% |
| High water table (limits basements) | 27.6% |
| Septic fields very limited | 88.8% |
| Clay swell (LEP, by area) | 11.1% |
| High-swell land (LEP 6%+) | 76.4% |
| Mapped soil | 7,041 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Lake Charles | 70% | 97% |
| Bernard | 22% | 43% |
| Edna | 6% | n/a |
| Verland | 1% | n/a |
| Cieno | 1% | n/a |
| Leton | under 1% | n/a |
What the numbers mean here
Clay swell averages a linear extensibility of 11.1% by land area here, and 76% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 76% of the mapped land.
Clay shrinks as it dries: 100% of Brazoria County is in drought on the latest map, and 76% of Iowa Colony's mapped land has shrink-swell clay.
On 28% of Iowa Colony's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates 89% of the land very limited for septic absorption fields.
Drought in Brazoria County
100% of Brazoria County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap Iowa Colony. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 77583 | over 99% | 403 | $23.5 million |
Homes in Iowa Colony
| Housing units | 4,683 |
| Median year built | 2015 |
| Built before 1980 | 2% |
| Built 2000 or later | 96% |
| Owner-occupied | 96% |
| Median value, owner-occupied | $405,700 |
| Single-family detached | 94% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Sandy Point | 4 mi | 74% | 34% |
| Manvel | 5 mi | 70% | 47% |
| Arcola | 5 mi | 80% | 23% |
| Bonney | 8 mi | 74% | 21% |
| Pearland | 10 mi | 70% | 36% |
| Missouri City | 11 mi | 58% | 29% |
| Alvin | 12 mi | 65% | 48% |
| Brookside Village | 12 mi | 69% | 56% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status