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Foundation soil risk by city

How expansive the ground is under 50 US cities, read from the USDA soil survey: the soil series mapped most often near each city center, its shrink-swell class and clay content, beside NOAA climate normals (frost days and annual precipitation) and the age of the housing.

Updated November 2, 2026 · 50 cities in 15 states · Published by FoundationRepairHQ

Short answer

Computed from the table below

36 of the 50 cities have at least one commonly mapped soil series with high or very high shrink-swell potential in the USDA soil survey (22 very high, 14 high; linear extensibility of 6% or more).

Texas accounts for 21 of those 36: 21 of its 25 cities in the table. Every city listed in Louisiana and Missouri also reaches the high class.

The highest linear extensibility recorded is 20.2% (Allemands, New Orleans), 19.8% (Sharkey, Baton Rouge), 18.7% (Victoria, Corpus Christi); 17 cities have a mapped series at 17% or more.

14 cities have no high-class soil among their most-mapped series, while in Frisco, Round Rock, Temple, Houston and Beaumont all 4 are high or very high.

In 23 cities the median home was built before 1980 (Census ACS 2022); 17 of them are high-shrink-swell cities.

Cities by highest shrink-swell class

Very High 22
High 14
Moderate 11
Low 3

Deep polygon shrinkage cracks in dark gray clay soil next to a brown St. Augustine lawn edge — Fig. 1Expansive clay in drought: the same soil swells back after heavy rain, and the slab rides that cycle.

All 50 cities

Shrink-swell is the highest NRCS class among each city's four most-mapped soil series, with its maximum linear extensibility (LEP) and the series it belongs to. Filter by state or class; select a heading to sort. Each city links to its full soil table.

State

Shrink-swell class

Sorted by shrink-swell (max lep), highest first. Select a column heading to re-sort.

Scroll the table sideways for all columns

Foundation soil risk by city: USDA soil survey shrink-swell class, clay and drainage, with NOAA climate and Census housing age

New Orleans	LA	Cancienne19% of mapped soils	Very High 20.2%Allemands	94%	Somewhat poorly drained	5	63.4 inNEW ORLEANS INTL AP, LA	1958
Baton Rouge	LA	Sharkey15% of mapped soils	Very High 19.8%Sharkey	84%	Poorly drained	18	61.9 inBATON ROUGE RYAN AP, LA	1975
Corpus Christi	TX	Victoria11% of mapped soils	Very High 18.7%Victoria	61%	Well drained	4	31.7 inCORPUS CHRISTI, TX	1980
Austin	TX	Eckrant6% of mapped soils	Very High 17%Heiden	55%	Well drained	12	36.3 inAUSTIN-CAMP MABRY, TX	1991
Frisco	TX	Altoga6% of mapped soils	Very High 17%Heiden	55%	Well drained	23	38.3 inDALLAS LOVE FLD, TX	2008
Georgetown	TX	Houston Black9% of mapped soils	Very High 17%Heiden	55%	Moderately well drained	12	36.3 inAUSTIN-CAMP MABRY, TX	2005
Jackson	MS	Providence16% of mapped soils	Very High 17%Byram	60%	Moderately well drained	40	57.4 inJACKSON INTL AP, MS	1970
Laredo	TX	Catarina12% of mapped soils	Very High 17%Catarina	51%	Moderately well drained	5	19.7 inLAREDO 2, TX	1995
McKinney	TX	Houston Black10% of mapped soils	Very High 17%Houston Black	55%	Moderately well drained	48	38.3 inMCKINNEY MUNI AP, TX	2006
Memphis	TN	Grenada12% of mapped soils	Very High 17%Sharkey	75%	Moderately well drained	44	54.9 inMEMPHIS INTL AP, TN	1970
Plano	TX	Eddy11% of mapped soils	Very High 17%Heiden	54%	Well drained	23	38.3 inDALLAS LOVE FLD, TX	1993
Round Rock	TX	Heiden9% of mapped soils	Very High 17%Heiden	55%	Well drained	12	36.3 inAUSTIN-CAMP MABRY, TX	2001
San Antonio	TX	Houston Black8% of mapped soils	Very High 17%Houston Black	55%	Moderately well drained	14	32.4 inSAN ANTONIO INTL AP, TX	1983
Shreveport	LA	Moreland11% of mapped soils	Very High 17%Moreland	69%	Somewhat poorly drained	30	51.4 inSHREVEPORT, LA	1973
St. Louis	MO	Menfro16% of mapped soils	Very High 17%Darwin	52%	Well drained	85	41.7 inST LOUIS LAMBERT INTL AP, MO	1938
Temple	TX	Heiden11% of mapped soils	Very High 17%Heiden	55%	Well drained	33	37 inSTILLHOUSE HOLLOW DAM, TX	1988
Waco	TX	Weswood7% of mapped soils	Very High 17%Heiden	68%	Well drained	34	36.4 inWACO RGNL AP, TX	1976
Houston	TX	Bernard11% of mapped soils	Very High 13.6%Lake Charles	61%	Somewhat poorly drained	4	55.6 inHOUSTON HOBBY AP, TX	1980
Kansas City	MO	Knox14% of mapped soils	Very High 11%Snead	61%	Well drained	93	38.1 inKANSAS CITY DOWNTOWN AP, MO	1968
Nashville	TN	Mimosa15% of mapped soils	Very High 9.2%Mimosa	61%	Well drained	66	50.5 inNASHVILLE INTL AP, TN	1984
Springfield	MO	Goss13% of mapped soils	Very High 9.2%Goss	70%	Well drained	95	44.7 inSPRINGFIELD, MO	1976
Beaumont	TX	Evadale6% of mapped soils	Very High 9%Evadale	55%	Poorly drained	8	62.1 inPORT ARTHUR SE TX AP, TX	1977
Arlington	TX	Frio4% of mapped soils	High 8.3%Frio	48%	Well drained	29	37 inDALLAS FT WORTH AP, TX	1984
Denver	CO	Elyria7% of mapped soils	High 8.3%Denver	50%	Well drained	156	15.4 inDENVER-STAPLETON, CO	1972
Tulsa	OK	Dennis5% of mapped soils	High 8.2%Niotaze	45%	Somewhat poorly drained	72	41 inTULSA INTL AP, OK	1972
Raleigh	NC	Wedowee7% of mapped soils	High 8%Creedmoor	53%	Well drained	65	46.1 inRALEIGH DURHAM INTL AP, NC	1995
Amarillo	TX	Olton7% of mapped soils	High 7.8%Pullman	48%	Well drained	108	19.7 inAMARILLO, TX	1972
Abilene	TX	Rowena7% of mapped soils	High 7.5%Rowena	43%	Well drained	48	25.2 inABILENE RGNL AP, TX	1974
Birmingham	AL	Nauvoo19% of mapped soils	High 7.5%Tupelo	55%	Well drained	47	56.6 inBIRMINGHAM AP, AL	1965
Dallas	TX	Eddy7% of mapped soils	High 7.5%Lewisville	46%	Well drained	23	38.3 inDALLAS LOVE FLD, TX	1979
Denton	TX	Navo5% of mapped soils	High 7.5%Navo	45%	Moderately well drained	29	37 inDALLAS FT WORTH AP, TX	1992
El Paso	TX	Harkey9% of mapped soils	High 7.5%Glendale	45%	Well drained	42	8.8 inEL PASO INTL AP, TX	1983
Fort Worth	TX	Gasil5% of mapped soils	High 7.5%Ovan	48%	Well drained	33	35.3 inFT WORTH MEACHAM FLD, TX	1990
Killeen	TX	Lewisville8% of mapped soils	High 7.5%Lewisville	50%	Well drained	31	34.8 inKILLEEN, TX	1994
Little Rock	AR	Carnasaw10% of mapped soils	High 7.5%Carnasaw	53%	Well drained	50	50.4 inLITTLE ROCK AP ADAMS FLD, AR	1978
Phoenix	AZ	Antho7% of mapped soils	High 7.5%Gilman	33%	Somewhat excessively drained	1	7.2 inPHOENIX SKY HARBOR INTL AP, AZ	1984
Oklahoma City	OK	Teller5% of mapped soils	Moderate 5.3%Norge	41%	Well drained	72	36.4 inOKLAHOMA CITY WILL ROGERS AP, OK	1981
Charlotte	NC	Cecil14% of mapped soils	Moderate 5%Mecklenburg	55%	Well drained	58	43.6 inCHARLOTTE DOUGLAS AP, NC	1993
Indianapolis	IN	Miami27% of mapped soils	Moderate 4.5%Miami	40%	Moderately well drained	106	43.6 inINDIANAPOLIS, IN	1971
Knoxville	TN	Dewey10% of mapped soils	Moderate 4.5%Dewey	69%	Well drained	67	51.9 inKNOXVILLE MCGHEE TYSON AP, TN	1973
Lubbock	TX	Posey10% of mapped soils	Moderate 4.5%Bippus	34%	Well drained	84	18.3 inLUBBOCK, TX	1982
Odessa	TX	Kimbrough9% of mapped soils	Moderate 4.5%Reagan	40%	Well drained	58	13.5 inMIDLAND ODESSA, TX	1977
Tampa	FL	Myakka6% of mapped soils	Moderate 4.5%Chobee	28%	Poorly drained	1	49.5 inTAMPA INTL AP, FL	1983
Tucson	AZ	Anthony10% of mapped soils	Moderate 4.5%Grabe	34%	Well drained	12	10.6 inTUCSON INTL AP, AZ	1979
Tyler	TX	Pickton11% of mapped soils	Moderate 4.5%Cuthbert	48%	Well drained	29	42.1 inTYLER POUNDS FLD, TX	1978
Midland	TX	Amarillo8% of mapped soils	Moderate 3.7%Kimbrough	34%	Well drained	58	13.5 inMIDLAND ODESSA, TX	1986
Columbia	SC	Vaucluse7% of mapped soils	Moderate 3%Nanford	50%	Well drained	47	45.2 inCOLUMBIA, SC	1977
Atlanta	GA	Madison12% of mapped soils	Low 2.5%Gwinnett	53%	Well drained	36	50.4 inATLANTA HARTSFIELD INTL AP, GA	1985
Jacksonville	FL	Pelham6% of mapped soils	Low 1.5%Pelham	29%	Poorly drained	14	53.4 inJACKSONVILLE, FL	1986
Orlando	FL	Candler7% of mapped soils	Low 1.5%Candler	6%	Excessively drained	2	51.5 inORLANDO INTL AP, FL	1990

Soil: USDA NRCS SSURGO via Soil Data Access, queried October 30, 2026. Precipitation and frost days (minimum ≤ 32°F): NOAA NCEI 1991–2020 Climate Normals, one named station per city, retrieved November 2, 2026. Median year built: Census ACS 5-year 2022. LEP 6% or more is the high class.

How the numbers were made

The same method as the soil section of every city page. Editorial policy

The soil query

For each city we draw a square about 0.3° on a side (roughly 10 miles from the center in each direction) around the city-center coordinate and ask USDA Soil Data Access for every SSURGO map unit that intersects it. Within those map units we keep major components only, drop urban land, water, pits, dumps, fill and rock outcrop, and group the components by soil series.

What “dominant” means

"Dominant" means the series with the largest summed component percentage across the intersecting map units — how often it is mapped, not how much area it covers. The four most-mapped series are kept; their share is of all remaining major components.

Shrink-swell class

Shrink-swell class comes from linear extensibility (LEP, the representative lep_r value), taking the highest value in any horizon of the series, and the NRCS classes: under 3% low, 3–6% moderate, 6–9% high, 9% or more very high. The city column shows the highest class among its four most-mapped series, because one expansive series under part of a city is what moves slabs there.

Climate and housing columns

Climate columns are NOAA NCEI 1991–2020 U.S. Climate Normals for one station per city, named in the data: the nearest first-order weather station (usually the airport) to the city-center coordinate with standard-completeness normals, else the nearest station with representative ones, within 25 miles. Annual precipitation is ANN-PRCP-NORMAL; frost days are ANN-TMIN-AVGNDS-LSTH032, the average number of days a year whose minimum temperature is 32°F or lower. That counts freezing nights, not freeze-thaw cycles, which NOAA normals do not publish. A station can sit up to about 20 miles from the city center, so treat the figures as the local climate, not your street. Median year built is the Census ACS 5-year 2022 estimate (table B25035) for the incorporated place.

Limitations

The 50 cities are the ones this site covers, half of them in Texas. They are not a random or representative sample of US cities, so counts describe this table, not the country.
One coordinate per city: the box around the city center does not cover the whole metro, and suburbs can sit on different soils.
Counts by mapped components are not area-weighted. A series can rank first because it appears in many small map units.
Soil survey values are representative values for a series, not measurements at an address. Soils change block by block; only a geotechnical report or an engineer reads your lot.
Shrink-swell is one factor. Drainage, trees, plumbing leaks, fill and construction quality decide whether a given house moves.

Columns

Citycity: City name
Statestate_abbr: Two-letter US state code
Latitudelatitude: Latitude of the city center used for the soil query (WGS84)
Longitudelongitude: Longitude of the city center used for the soil query (WGS84)
Dominant soil seriesdominant_series: Most frequently mapped major soil series within about 10 miles of the city center (USDA NRCS SSURGO)
Dominant series sharedominant_share_pct: Share of mapped major-component percentages held by the dominant series (not area-weighted) (percent)
Shrink-swell classshrink_swell_class: Highest NRCS linear-extensibility class among the four most-mapped series: Low <3%, Moderate 3–6%, High 6–9%, Very High ≥9%
Max LEPmax_lep_pct: Highest representative linear extensibility (lep_r) in any horizon of the four most-mapped series (percent)
Max LEP seriesmax_lep_series: Soil series with the highest linear extensibility
High-class serieshigh_series: Number of the most-mapped series in the high or very high shrink-swell class
Series countedseries_counted: Number of most-mapped major soil series examined (up to four)
Max claymax_clay_pct: Highest representative total clay (claytotal_r) in any horizon of the most-mapped series (percent)
Drainage (dominant series)dominant_drainage: NRCS drainage class most often reported for the dominant series
Frost days (min ≤ 32°F)frost_days: Average number of days a year with a minimum temperature at or below 32°F (NOAA NCEI 1991–2020 Climate Normals, ANN-TMIN-AVGNDS-LSTH032). A count of freezing nights, not of freeze-thaw cycles (days per year)
Annual precipitationannual_precip_in: Normal annual precipitation (NOAA NCEI 1991–2020 Climate Normals, ANN-PRCP-NORMAL) (inches)
NOAA stationnoaa_station_id: GHCN-Daily id of the normals station used for the two climate columns (nearest first-order station to the city center with complete normals)
NOAA station namenoaa_station_name: Station name as published by NOAA NCEI
Median year builtmedian_year_built: Median year structure built, all housing units (US Census Bureau ACS 5-year 2022, table B25035)
City pageurl: URL of the FoundationRepairHQ city page with the full soil table

Sources

USDA NRCS Soil Survey Geographic Database (SSURGO), via Soil Data Access — soil series, linear extensibility, clay, drainage
NOAA NCEI U.S. Climate Normals 1991–2020 (annual/seasonal), one station per city — annual precipitation and frost days (minimum ≤ 32°F)
US Census Bureau, American Community Survey 5-year estimates 2022 (B25035) — median year built

Soil profiles queried October 30, 2026; NOAA normals retrieved November 2, 2026; housing values compiled March 21, 2026.

How to cite

For articles, reports and AI answers that use these numbers.

FoundationRepairHQ, "Foundation soil risk by city", 2026, https://www.foundationrepairhq.com/data/foundation-soil-risk

License: CC BY 4.0 — copy, adapt and republish, including commercially, as long as you credit FoundationRepairHQ and link to this page. Soil values are USDA NRCS public data; credit the soil survey too when you quote them. When quoting one city, link its city page.