Soil series profile
Harlingen soil series
Harlingen is a moderately well drained soil with a clay surface, mapped on 97,902 acres in 2 counties in TX. Hydrologic group D.
- Drainage class
- Moderately well drained 94% of mapped acres
- Hydrologic group
- D 94% of mapped acres
- Typical topsoil pH
- 8.2 moderately alkaline · range 8.2–8.2
- Mapped area
- 98k acres in 2 counties, 1 state
Typical Harlingen profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–11 in (H1) | Clay | 8.2 | 55% | 17% | 2% |
| 11–35 in (H2) | Clay | 8.2 | 68% | 10% | 1.5% |
| 35–71 in (H3) | Clay | 8.2 | 63% | 11% | 0.75% |

What this means
What Harlingen soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Harlingen soils is moderately alkaline: pH 8.2. Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Clayey topsoil covers 94% of mapped Harlingen acres. Clay holds water and nutrients but drains slowly and compacts if worked wet: add compost, avoid tilling soggy soil and consider raised beds. The most common surface texture is clay (94% of mapped Harlingen acres).
>99% of mapped Harlingen acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 94% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For a septic system
For conventional septic absorption fields, NRCS rates 94% of the acres in mapped Harlingen soils very limited, 0% somewhat limited and 0% not limited (6% not rated, such as urban land, pits or water).
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Harlingen soil is found
Mapped acres
Harlingen is mapped in Texas.
| County | Acres | Share of county land |
|---|---|---|
| Cameron County, TX | 52,018 | 8.5% |
| Hidalgo County, TX | 45,884 | 4.6% |
Septic absorption fields
NRCS rating, share of Harlingen acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 94.2% |
| Not rated | 5.8% |
Drainage, water table and flooding
Share of Harlingen acres
- Depth to seasonal high water table
- None reported within about 6.5 feet (median where reported).
- Flooding
- Mapped as flooding on 5% of acres (0% occasional, 0% frequent).
- Slope
- Typically 0–0% (median 0%).
- Topsoil organic matter
- Median 2%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 5.5% |
| Moderately well drained | 94.2% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 0.3% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 0.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 94.2% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 0.0% |
| C/D: D as is, C if drained | 0.0% |
| Not rated | 5.8% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named Harlingen (component kind "Series") in SSURGO: 97,902 acres.
- Method
- Shares are by mapped acres of Harlingen components. The profile comes from the single largest Harlingen component. Full methodology.