Soil Conditions in Compton
Los Angeles County's geology is as varied as its neighborhoods. Here's what we typically find.
Deep LA Basin Alluvium
Compton lies on deep Quaternary alluvial deposits within the central LA Basin. The subsurface consists of interbedded clays, silts, sands, and gravels deposited by the Los Angeles River and Compton Creek systems. These deposits extend to great depth, and soil conditions can vary significantly over short horizontal distances.
High Water Table and Liquefaction
Groundwater in Compton is generally shallow, often within 10 to 25 feet of the surface. Much of the city is mapped within CGS liquefaction hazard zones due to the combination of loose sandy alluvium and high groundwater. Liquefaction-induced settlement is the primary seismic hazard for most Compton properties.
Expansive and Compressible Clays
Clay-rich alluvial deposits with moderate to high expansion potential are common throughout Compton. These soils undergo volume change with moisture fluctuation, which can crack foundations, heave flatwork, and damage utilities. Soft compressible clays may also be present at depth, contributing to long-term settlement under structural loads.
Former Oil Production Areas
The Dominguez Oil Field extends into portions of western Compton. Properties near former oil wells may encounter abandoned well casings, variable fill, and potential soil or groundwater contamination. Methane gas evaluation may be warranted for development near historical oil production sites.
What We Do in Compton
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/WQMP 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 Compton
Single-Family Home
New homes and rebuilds in Compton's residential areas require geotechnical reports addressing liquefaction, expansive soils, and shallow groundwater — the three most common subsurface challenges in the city.
ADU / Accessory Dwelling Unit
ADU construction is increasing in Compton as homeowners add housing. A soils report is required and is especially important given the widespread liquefaction hazard across the city.
Industrial and Warehouse
Industrial development along Alameda Street and in the western industrial corridor requires geotechnical investigation for slab-on-grade design, with attention to liquefaction-induced differential settlement.
Affordable Housing
Compton has seen investment in affordable housing projects that require full geotechnical and civil engineering services including soils reports, grading plans, and stormwater compliance documentation.
Working With City of Compton Development Services Department
Compton Development Services requires geotechnical reports for new construction and grading permits. The city uses contract plan check services for technical review. Given the extensive liquefaction hazard zones across the city, a liquefaction analysis is expected for virtually all geotechnical reports.
What Makes This Jurisdiction Distinct
Liquefaction analysis required for most properties citywide due to extensive CGS-mapped hazard zones
Geotechnical report must address expansive soil potential and recommend appropriate foundation mitigation
Methane gas evaluation may be required for properties near the Dominguez Oil Field
WQMP with LID compliance required for new development per LA County MS4 Permit
Hydrology study required for projects within the Dominguez Channel watershed
Submit geotechnical reports and civil engineering plans to Compton Development Services with the permit application. The city uses contract plan check engineers, and processing times vary. Early consultation with Development Services is recommended to confirm investigation requirements.
Common Questions — Compton
Building in Compton?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.