Soil Conditions in Costa Mesa
Orange County presents a range of subsurface conditions. Here's what we encounter most frequently.
Marine Terrace and Coastal Deposits
Costa Mesa is underlain by Pleistocene marine terrace deposits consisting of fine to medium sands, silty sands, and interbedded clay layers deposited in a nearshore marine environment. These soils are generally medium dense to dense but can be loose and susceptible to liquefaction in saturated zones near the surface.
Shallow Groundwater
Groundwater in Costa Mesa is relatively shallow, commonly encountered at 10 to 25 feet below the surface and sometimes shallower in low-lying areas near the Santa Ana River and along the mesa bluffs. Shallow water conditions influence foundation design, require dewatering for excavations, and contribute to liquefaction risk.
Newport-Inglewood Fault Proximity
The Newport-Inglewood fault zone passes through the southern portion of Costa Mesa. While most of the city is outside the Alquist-Priolo fault zone, proximity to this active fault means that seismic design considerations and strong ground motion are important factors in geotechnical recommendations for all Costa Mesa projects.
What We Do in Costa Mesa
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 Costa Mesa
ADU / Accessory Dwelling Unit
Soils reports and foundation recommendations for ADUs across Costa Mesa's residential neighborhoods on both the mesa top and lower-lying areas.
Mixed-Use Development
Geotechnical and civil engineering for mixed-use projects along Harbor Boulevard, 19th Street, and the South Coast Metro area.
Commercial Redevelopment
Foundation investigation and site grading for retail and office redevelopment in Costa Mesa's commercial corridors and the South Coast Plaza vicinity.
Industrial Conversion
Geotechnical evaluation and civil engineering for adaptive reuse of industrial properties into creative office, retail, and live-work spaces in the Westside neighborhood.
Working With City of Costa Mesa Development Services Department
Costa Mesa's Development Services Department handles plan check for building, grading, and encroachment permits. Geotechnical reports are reviewed by the city's contract geotechnical consultant, and grading plans are reviewed by the Public Services Division. The department is organized for efficient processing and staff are accessible for pre-submittal questions.
What Makes This Jurisdiction Distinct
Liquefaction analysis required for projects in state-mapped hazard zones throughout low-lying areas
WQMP required per Santa Ana Regional Water Quality Control Board MS4 permit
Bluff setback and stability evaluation required for properties near mesa bluffs
Methane mitigation may be required for properties near former oil production sites
Projects in South Coast Metro area may be subject to additional specific plan requirements
Costa Mesa accepts electronic plan submittals through its permitting portal. The city offers over-the-counter permits for certain minor projects. For larger projects, a pre-application meeting with Development Services staff is recommended to clarify submittal requirements.
Common Questions — Costa Mesa
Building in Costa Mesa?
Tell us about your project and we'll send you a fixed-fee proposal — typically within one business day.