Soil Conditions in San Diego
San Diego's geology varies dramatically from neighborhood to neighborhood. Here's what we see most often.
Lindavista Formation — Terrace Deposits
Much of central and coastal San Diego sits on the Lindavista Formation, an ancient marine terrace deposit of reddish-brown sandy clay and silty sand. These soils are generally firm and offer good bearing capacity but can be moderately expansive. Foundation design typically accounts for expansion potential in the upper 3-5 feet.
Bay and Estuarine Clays
Near Mission Bay, San Diego Bay, and the San Diego River valley, soft compressible bay clays and organic-rich estuarine deposits are common. These soils have low bearing capacity and high settlement potential, often requiring deep foundations or ground improvement for heavier structures.
Friars Formation — Landslide-Prone Clay
The Friars Formation, a massive clay-rich unit, is exposed throughout Mission Valley and the surrounding mesas. It is notorious for slope instability and has been the source of numerous landslides in San Diego. Projects on or near Friars Formation slopes require detailed slope stability analysis.
Rose Canyon Fault Zone
The Rose Canyon fault extends through the coastal areas of San Diego from La Jolla south through downtown. Sites within the Alquist-Priolo zone require fault rupture hazard investigations. Seismic ground shaking and potential liquefaction near the bay and river valleys are key design considerations.
What We Do in San Diego
Soils Reports
Geotechnical investigation and foundation recommendations for building permits.
Learn more →Grading Plans
Precise and rough grading design with drainage and earthwork calculations.
Learn more →Compaction Testing
Field density testing and fill certification for construction.
Learn more →Stormwater / LID / WQMP
LID compliance, WQMP preparation, and BMP design.
Learn more →Hydrology Reports
Drainage analysis and flood risk assessment.
Learn more →Subsurface Exploration
Drilling, CPT, and test pit programs.
Learn more →Erosion Control Plans
SWPPP and erosion control for grading permits.
Learn more →Street Improvements
Frontage, curb, gutter, and sidewalk design.
Learn more →Utility Plans
Water, sewer, and storm drain design and coordination.
Learn more →Project Coordination
One point of contact managing structural, MEP, surveying, and specialty consultants.
Learn more →We also coordinate with your structural engineer, architect, MEP consultants, and other project team members to ensure our deliverables integrate with the overall design — one point of contact for your geotechnical and civil engineering scope.
What People Build in San Diego
ADU / Casita
San Diego leads California in ADU permits. Most require a soils report and grading plan, especially on sloped lots.
Hillside Custom Home
The canyons and mesas of San Diego create challenging hillside building sites that require detailed geotechnical and civil engineering.
Pool & Retaining Wall
Backyard pools and retaining walls on San Diego's varied terrain often need soils reports for slope stability and lateral earth pressure design.
Commercial Mixed-Use
Infill commercial and mixed-use projects in urban San Diego often encounter variable fill conditions and require deep foundation analysis.
Working With City of San Diego Development Services Department (DSD)
The City of San Diego requires a geotechnical investigation for most new construction, additions over 50%, and grading permits. Reports are reviewed by DSD geotechnical staff. Plan check typically involves a first review followed by one or more correction cycles.
What Makes This Jurisdiction Distinct
Environmentally Sensitive Lands (ESL) overlay may trigger additional slope stability and drainage analysis
Multi-Species Conservation Program (MSCP) compliance required in mapped areas
Community Plan updates may impose supplemental geotechnical or drainage requirements
Storm Water Standards Manual compliance required — Priority Development Projects need a SWQMP
Hillside review process for slopes steeper than 25% or grading on 2:1 or steeper
Submit through the DSD online portal or in person at 1222 First Avenue. Plan check typically takes 4-6 weeks for first review. Expedited review is available for an additional fee.
Common Questions — San Diego
Building in San Diego?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.