Soil Conditions in Riverside
Riverside County's Inland Empire soils range from deep alluvial fan deposits to weathered granitic bedrock. Here's what we encounter most often.
Alluvial Fan Deposits
Much of the City of Riverside sits on alluvial fan deposits shed from the San Bernardino and Box Springs Mountains. These soils range from loose sands and silty sands near the surface to dense gravelly materials at depth. Foundation design must account for variable density and the potential for differential settlement in areas of younger alluvium.
Expansive Soils in Valley Areas
The valley floor and lower terrace areas frequently contain clay-rich soils with moderate to high expansion potential. Expansive soils can cause significant damage to slabs, foundations, and flatwork if not properly mitigated. Geotechnical investigations in these areas typically recommend moisture conditioning, deepened footings, or post-tensioned slabs.
Older Formational Soils — Arlington Heights
The Arlington Heights area and surrounding hills expose older formational soils and weathered bedrock that behave very differently from the valley alluvium. These materials can have high bearing capacity but may also include cemented layers that complicate excavation. Slope stability analysis is often required for hillside projects in these areas.
Seismic Considerations — San Jacinto Fault Zone
The San Jacinto fault zone passes near the eastern margin of Riverside, making seismic design a primary concern for all new construction. Site-specific seismic hazard analysis must address ground shaking, liquefaction potential in loose alluvial soils, and seismically induced settlement. The 2022 CBC seismic design parameters vary significantly across the city depending on proximity to the fault.
What We Do in Riverside
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 Riverside
Single-Family Homes & ADUs
New home construction and accessory dwelling units throughout Riverside neighborhoods, including infill development near downtown and new subdivisions in the eastern portions of the city.
UC Riverside Area Development
Student housing, mixed-use commercial, and institutional projects in the University Avenue corridor and surrounding neighborhoods driven by campus expansion.
Industrial & Warehouse
Large-footprint tilt-up and steel buildings along the I-215 and SR-60 corridors serving Inland Empire logistics and distribution demand.
Hillside Custom Homes
Hillside residential projects in the Arlington Heights, Hawarden Hills, and Alessandro Heights areas requiring slope stability analysis and specialized grading design.
Working With City of Riverside — Community & Economic Development Department
The City of Riverside requires a geotechnical investigation for all new construction and grading permits involving more than 50 cubic yards of cut or fill. Soils reports must be prepared by a licensed geotechnical engineer (GE) and grading plans by a licensed civil engineer (RCE). Plan check submittals go through the Community & Economic Development Department, which coordinates review with Public Works for drainage and stormwater.
What Makes This Jurisdiction Distinct
Grading permits required for earthwork exceeding 50 cubic yards of cut or fill
Geotechnical report with expansion index testing required for all new foundations
WQMP required for new development and redevelopment projects per the Santa Ana Region MS4 permit
Seismic hazard evaluation required for sites within mapped fault zones or liquefaction zones
Erosion control plan (SWPPP) required for projects disturbing one acre or more
The City of Riverside uses an electronic plan check submittal system. Geotechnical reports and grading plans should be submitted as sealed PDF files. Allow 4-6 weeks for initial review. Expedited review is available for an additional fee.
Common Questions — Riverside
Building in Riverside?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.