California Soil Testing Inc.
Residential soil reports & geotechnical investigation across the Bay Area, Monterey County & Sacramento
California Soil Testing Inc. specializes in geotechnical investigation that provides soil reports with recommendations for foundation, drainage, and grading for residential projects: homes, ADUs, additions, decks, and pools. We deliver the PE-stamped soil reports and field testing that get your project through plan check, backed by our own in-house laboratory and a 4-week turnaround guarantee.
From the first boring to final inspection
Residential soil reports are our specialty. Every project starts with a real subsurface investigation (borings, sampling, and lab testing) and ends with clear foundation and grading recommendations your designer, engineer, and building department rely on. You build it; we tell you what the soil can support.
Soil Reports & Geotechnical Studies
PE-stamped foundation investigation reports required for residential building permits. Each boring feeds lab-tested data into foundation, drainage, and grading recommendations.
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Compaction & Backfill Testing
Field density and backfill compaction testing with approved nuclear gauges (ASTM D6938) to verify your fill, subgrade, and trench backfill meet the compaction specs on your grading plan.
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Liquefaction Studies & CPT Testing
Site-specific evaluations of earthquake-induced ground deformation, required within state-designated seismic hazard zones. CPT testing (ASTM D5778) permitted to 50 ft below grade.
Learn more →A straightforward process, start to finish
Same-day quote
Send us your address and project description. You'll have a fixed-price proposal within 24 hours, usually the same day.
Site investigation
We drill borings or excavate test pits, log the soil profile, and collect samples for laboratory analysis.
In-house testing
Samples are tested in our own laboratory per ASTM and AASHTO standards, with no third-party delays.
PE-stamped report
You receive a signed, stamped geotechnical report ready for submittal, within our 4-week turnaround guarantee.
A locally owned firm with an engineer's discipline
We keep our lab in-house, our pricing low, and our phones answered. When you call, you talk to the people doing the work, not a call center.
In-house laboratory
Project-specific testing in full compliance with AASHTO and ASTM standards, under our own roof. Faster results, tighter quality control.
Speed & pricing
Low prices, same-day quotes and proposals, and a 4-week report turnaround guarantee that keeps your permit timeline on track.
Responsive support
Immediate telephone consultation and a friendly, locally owned approach. Your questions get answered by an engineer, not a voicemail.
Serving the Bay Area and Surrounding Regions
Shaded regions show our primary service areas. Don't see your city? Call us; we likely cover it.
Ready to break ground?
Get a fixed-price quote and a professional geotechnical scope for your project within 24 hours.