Williamson County Foundation Stress Index

How much stress are WilCo’s clay soils putting on foundations right now? This gauge reads two public climate feeds — the U.S. Drought Monitor and NOAA’s county climate record — and scores the current shrink-swell conditions for the county.

What’s feeding the gauge right now

Live data is temporarily unavailable — the feeds this gauge reads update weekly (Drought Monitor, Thursdays) and monthly (NOAA county data). Check back shortly, or read on for how the cycle works: it’s the swing between drought and heavy rain that moves foundations here, not any single dry or wet week.

Why drought-then-rain is what cracks foundations here

The Blackland clay under the eastern half of Williamson County behaves like a sponge. In a drought it dries and contracts, and the soil pulls away from the slab — support drops away first at the exposed edges. When heavy rain follows, the clay expands and pushes back up, unevenly, because the protected soil under the middle of the house never dried as far. That down-then-up flex — not dryness or wetness by itself — is what walks a slab out of level, which is why this index watches for the swing: weeks of drought followed by above-normal rain. The soil map shows whether your area sits on the clay that responds this way, and the east-county explainer covers the mechanics in depth.

What each level means for you

LOW

Soil moisture is near normal and stable. Nothing seasonal to act on — a fine time for cheap prevention like fixing gutter downspouts and grading low spots.

MODERATE

Conditions are drifting — a drought is building, or recent rain is re-wetting soil that had dried. Watch doors that start to stick and hairline cracks; keep watering consistent if restrictions allow (see the watering advisor).

ELEVATED

The county is in, or swinging out of, a real drought. Movement-prone areas — Hutto, Taylor, Pflugerville and the east side generally — commonly see seasonal symptoms now. Track anything new with the crack checker before deciding it’s structural.

HIGH

A strong contraction-then-expansion cycle is underway — the conditions that produce the most foundation claims on Blackland clay. New diagonal cracks, doors that jam, or a slab edge that looks lifted are worth an engineer’s look rather than waiting out the season.

Common questions

Does a HIGH reading mean my foundation is being damaged?

No. It means regional conditions are the kind that stress clay-supported foundations. Most homes ride out even severe cycles without damage — drainage and steady moisture are the difference-makers.

Why does rain raise the index? Isn’t rain good after a drought?

For lawns, yes. For a slab on clay that spent months contracting, a fast re-wetting is exactly when uneven movement happens. The index scores the swing, not the rain itself.

How often does it update?

The Drought Monitor publishes every Thursday; NOAA’s county climate data lands monthly. The gauge re-pulls both on a rolling basis, so a Thursday drought change shows up the same day.

Data sources

Drought category and weeks-in-drought come from the U.S. Drought Monitor county statistics API (Williamson County, FIPS 48491; the USDM is produced by NDMC, USDA and NOAA). Temperature and precipitation departures from normal come from NOAA NCEI nClimGrid county data (1901–2000 base period). The scoring bands are ours and are documented in the page source — treat the result as an indicative signal, not engineering advice.