Madera, California: what the ground under the city is like
Madera sits in Madera County, on california central valley. The soil mapped here is predominantly classified well drained — and that classification, not the rainfall total, is what decides how a slab foundation behaves.
Linear extensibility 11.9% — very high.
33% of the mapped soil area around Madera is wet enough that the USDA describes it as needing artificial drainage.
Shallowest annual water table around 150 cm (4.9 ft).
Values are for Madera County, which is what the soil survey resolves to. Full county report · soil map for a specific address.
The ground under Madera
California Central Valley. Alluvial fan and basin deposits, expansive clays in the basins, hardpan at depth
Expansive basin clays alternating with free-draining fan sediments, plus a cemented hardpan in places that perches water above it. Add the largest human-caused land subsidence in the country from groundwater pumping, and differential movement here has three separate causes.
When it shows up here
| Slab moisture | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ground movement | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
The opposite calendar to most of the country: the wet season runs from November to March and the summer is dry. A basement here is tested in January, not in April.
Climate pattern for this physiographic region, not a forecast for your house and not from the soil survey. It answers a question homeowners actually ask: when does this show up.
What repairs cost in California
| Reference job | Modelled range |
|---|---|
| Slab foundation lifted and stabilised on 12 piers | $22,300–$47,600 |
| Two slab cracks injected + regrading around the perimeter | $2,500–$8,300 |
| Engineer's report plus buried downspout discharge | $1,600–$5,450 |
Regional factor for CA: ×1.24. Full cost breakdown for California · run your own dimensions.
ZIP codes in Madera
93636, 93637, 93638, 93639
Soil does not stop at a city boundary, and neither does this data — every ZIP code above resolves to the same county soil survey. For the individual survey polygons around one address, use the soil map.
Questions about Madera
Is the soil the same everywhere in Madera?
No. These values describe Madera County as a whole, which is the unit the soil survey publishes. Within a city, map units change over a few hundred metres — the soil map draws the actual polygons around a point and is the honest answer for one address.
Which contractor should I call in Madera?
We do not rank or recommend individual firms and we are not one. What this page is for is knowing which kind of work the ground here points to before anyone quotes you, and which claim to check. If you want quotes, the form below passes your request to the named networks.
Does this replace an inspection?
No. It tells you what the ground is; an inspection tells you what your building is doing on it. The useful order is: read this, print the brief for your county, then have someone look.
Get quotes in Madera
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Page data updated