Starr County, Texas
Shrink-swell clay limits houses without basements on 14% of Starr County's mapped land, a higher share than 61% of US counties. A shallow water table limits basements on 1%.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 34 flood losses here since 2016, 0% of them in buildings with basements. 20% of homes were built before 1980, against 50% nationally; the median home dates from 1994.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Starr County
| Expansive clay (limits slab homes) | 13.9% |
| High water table (limits basements) | 0.9% |
| Septic fields very limited | 45.1% |
| Clay swell (LEP, by area) | 3.6% |
| High-swell land (LEP 6%+) | 13.9% |
| Mapped soil | 786,919 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| McAllen | 31% | n/a |
| Copita | 13% | n/a |
| Zapata | 8% | n/a |
| Brennan | 7% | n/a |
| Catarina | 6% | n/a |
| Ramadero | 6% | n/a |
How we count · survey areas TX427 (2025-09-04)
What the numbers mean here
Rain over the 12 months to August 2026: 14.92 in, 6.86 in below the 1991-2020 average year of 21.78 in.
With shrink-swell clay on 14% and a shallow water table on 1% of the land, the soil survey points to neither problem across most of Starr County; conditions still vary lot by lot.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 42 of the last 52 weeks; the most was 100% of its area, in 33 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
34 flood losses since 2016, $1.4 million paid. The worst year was 2020, with 13. Foundations of the buildings, where recorded: 96% slabs, 4% crawl spaces.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 0 |
| 2018 | 3 |
| 2019 | 1 |
| 2020 | 13 |
| 2021 | 0 |
| 2022 | 4 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 9 |
| 2026 to date | 2 |
Rain
| Average year, 1991-2020 | 21.78 in |
| 12 months to August 2026 | 14.92 in (-6.86) |
| 2025 | 15.75 in (-6.03) |
| Wettest year since 1895 | 1967: 40.89 in |
| Driest year since 1895 | 1898: 7.68 in |
| Days with 1 inch or more, normal at RIO GRANDE CITY (11 mi away) | 6.7 |
Homes
| Housing units | 23,139 |
| Median year built | 1994 |
| Built before 1980 | 20% |
| Built 2000 or later | 38% |
| Owner-occupied | 70% |
| Median value, owner-occupied | $95,100 |
| Single-family detached | 80% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Cities in Starr County
| City | Expansive clay | High water table | Homes |
|---|---|---|---|
| Escobares | 19% | 3% | 912 |
| La Grulla | 11% | 4% | 524 |
| Rio Grande City | 7% | 1% | 5,168 |
| Roma | 11% | 0% | 4,134 |
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Hidalgo County, TX | 36 mi | 12% | 6% |
| Jim Hogg County, TX | 36 mi | under 1% | under 1% |
| Zapata County, TX | 42 mi | 17% | under 1% |
| Brooks County, TX | 48 mi | 1% | 9% |
| Willacy County, TX | 71 mi | 18% | 34% |
| Kenedy County, TX | 75 mi | 1% | 39% |
| Duval County, TX | 81 mi | 4% | under 1% |
| Cameron County, TX | 84 mi | 29% | 26% |
Sources: USDA SSURGO (September 4, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status