Soil Conditions in San Bernardino
San Bernardino County sits at the transition from coastal influence to high desert — creating a wide range of soil conditions and seismic considerations. Here's what we typically find.
San Andreas Fault Zone Proximity
The City of San Bernardino sits adjacent to the San Andreas fault zone, placing most of the city in Seismic Design Category D or higher. Foundation design must account for strong ground motion, and fault rupture hazard zones require setback investigations for structures near mapped traces.
Alluvial Fan Deposits
Much of the city is built on alluvial fan deposits originating from the San Bernardino Mountains. These soils range from coarse gravelly sands near the mountain front to silty sands and clays in the lower elevations, with bearing capacities that vary significantly across short distances.
Liquefaction Susceptibility
Lowland areas near the Santa Ana River and its tributaries contain loose, saturated sandy soils susceptible to liquefaction during seismic events. Projects in these zones typically require liquefaction analyses and may need ground improvement or deep foundations to mitigate settlement risk.
Artificial Fill and Older Alluvium
Portions of the city, particularly redeveloped areas and former industrial sites, contain artificial fill of variable composition and density. Older alluvial deposits are generally denser and more competent, but site-specific investigations are needed to distinguish fill from native material.
What We Do in San Bernardino
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
WQMP preparation and BMP design for stormwater compliance.
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 Bernardino
Infill Single-Family Homes
New construction on vacant lots within established neighborhoods, requiring soils reports addressing fault proximity and variable alluvial conditions.
Warehouse & Industrial
Large-footprint tilt-up and steel buildings in industrial corridors along I-215 and I-10, often requiring deep alluvial characterization and slab-on-grade design.
Multi-Family & Affordable Housing
Apartment and affordable housing developments throughout the city, requiring geotechnical investigation, grading plans, and stormwater compliance.
ADU / Accessory Dwelling Unit
Garage conversions and detached ADUs on existing residential lots, typically requiring a soils report if the ADU exceeds 750 square feet or involves new foundations.
Working With City of San Bernardino Community Development & Housing Department
The City of San Bernardino requires geotechnical investigations for new construction, grading permits, and significant additions. Due to staffing limitations, plan check review periods can be longer than surrounding jurisdictions. Submitting a thorough and complete package on the first round is critical to avoiding delays.
What Makes This Jurisdiction Distinct
Alquist-Priolo fault rupture hazard investigation required for parcels within mapped San Andreas fault zone
Liquefaction analysis required for projects in designated liquefaction hazard zones near the Santa Ana River corridor
Grading plans must include erosion control measures and comply with the city's hillside grading ordinance where applicable
WQMP required under the Santa Ana Regional Board MS4 permit for new development and significant redevelopment
Allow extra lead time for plan check reviews. The Community Development department processes geotechnical and grading submittals sequentially, and resubmittals restart the queue. Digital submittals are accepted.
Common Questions — San Bernardino
Building in San Bernardino?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.