Foundation Repair & House Leveling in Harlingen, TX.

Harlingen sits on the type locality of the Harlingen clay series — a fine, smectitic, hyperthermic Sodic Haplusterts mapped by the USDA across most of Cameron County.

Plasticity index typically runs 40–60, liquid limit often above 70, and shrink-swell potential is rated 'very high.' The Arroyo Colorado threading through town acts as a moisture wick: soils within a half-mile of the arroyo stay near field capacity even in drought, while soils a few blocks away dry to the wilting point and crack open 2–4 inches at the surface.

That moisture differential — not the absolute moisture level — is what drives differential settlement under Dixieland, downtown, and Treasure Hills slabs.

Sodium content from old marine parent material also keeps soil resistivity low (often 1,500–3,000 ohm-cm), which accelerates corrosion of any buried steel without a robust passivating system.

Newer Stuart Place builds add a layer of imported fill that consolidates for 10–15 years over the same active clay below.