Soil Conditions in Fullerton
Orange County presents a range of subsurface conditions. Here's what we encounter most frequently.
Alluvial Fan and Terrace Deposits
Fullerton occupies an alluvial fan and elevated terrace position at the northern edge of the Orange County coastal plain. Quaternary-age alluvial deposits consisting of sands, gravels, silts, and clays provide the foundation soils for most of the city, with generally good bearing capacity in the sandy and gravelly zones.
La Habra Formation (North Fullerton Hills)
The hills in northern Fullerton are underlain by the La Habra Formation, a Pliocene-age unit of poorly consolidated sands, silts, and conglomerates. These soils can be erosion-prone and settlement-sensitive, and hillside grading must be carefully designed to manage stability and drainage.
Expansive Soils in Flatland Areas
Clay-rich soils with moderate to high expansion potential are common in the central and southern portions of Fullerton. Expansion indices of 40 to 80 are typical in these areas, and pre-saturation of building pads or use of post-tensioned slab foundations is often recommended to mitigate differential movement.
What We Do in Fullerton
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, LID compliance, 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 Fullerton
ADU / Accessory Dwelling Unit
Soils reports and grading plans for ADU construction in Fullerton's residential areas, including both flatland and hillside properties.
Hillside Residential
Slope stability analysis and grading design for new homes and additions in the north Fullerton hills, including compliance with the Hillside Development Ordinance.
University-Adjacent Mixed-Use
Geotechnical and civil engineering for mixed-use projects near Cal State Fullerton and Fullerton College.
Downtown Infill
Foundation investigation and site engineering for redevelopment projects in the Downtown Fullerton Specific Plan area.
Working With City of Fullerton Community Development Department
Fullerton's Community Development Department handles building and grading permit review. The Engineering Division within Public Works reviews grading plans and stormwater compliance documents. Geotechnical reports are reviewed by a contract geotechnical consultant retained by the city. Standard plan check runs 3 to 5 weeks for residential and 5 to 7 weeks for commercial projects.
What Makes This Jurisdiction Distinct
Hillside Development Ordinance applies enhanced requirements for properties in the north Fullerton hills
Whittier fault zone investigation required for properties within the Alquist-Priolo zone in northeast Fullerton
WQMP required per Santa Ana Regional Water Quality Control Board MS4 permit
Grading permits require designation of a geotechnical engineer of record for field observation
Street improvement dedications and public improvements may be required as conditions of development
Fullerton accepts electronic plan submittals and maintains regular counter hours for plan check inquiries. The city strongly encourages pre-application meetings for projects involving hillside development or properties near the Whittier fault zone.
Common Questions — Fullerton
Building in Fullerton?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.