Custom House Plans in California

Building requirements

Building a house in California: what the code requires

Statewide residential code

Building code

California Residential Code (Title 24, Part 2.5) applies statewide, with local amendments common in larger cities.

Energy code

California Energy Code (Title 24, Part 6) is one of the strictest in the US. New homes generally require solar PV, and all-electric readiness rules apply.

Climate zone

IECC climate zone 2–6. Insulation, windows and HVAC are sized to match.

Typical frost depth

0–12 in (coast/valleys), 18–36 in (mountains). Footings must extend below the local frost line (confirm with your building department).

Foundations

Raised or pier foundations where flood zones apply; slab inland.

Who can draw the plans

Single-family homes can generally be designed by a non-licensed home designer. A licensed engineer's stamp is often required for structural items, engineered foundations or special hazard zones, or when the local building official asks for it.

Engineer stamp

If your jurisdiction requires sealed drawings, add our California Engineer Stamp / Permit-Ready package ($1,500).

California-specific rules & hazards

• ●CALGreen (Title 24, Part 11) green-building requirements apply to all new homes.
• ●Wildland-Urban Interface areas (Fire Hazard Severity Zones) require Chapter 7A ignition-resistant construction.
• ●Seismic design is required statewide, and plans often need engineered lateral (shear wall) calculations.
• ●Coastal Commission permits may apply within the coastal zone.
• ●Seismic bracing, shear walls and hold-downs
• ●Wildfire-resistant materials and defensible-space detailing
• ●Flood-zone elevation and coastal foundation requirements

Summary for planning only. Codes, editions and local amendments change, so always confirm current requirements with the building department that will issue your permit. Our designers check your jurisdiction before drawing.

City building requirements in California

• Los Angeles, CAPermits, zoning & local rules →
• San Diego, CAPermits, zoning & local rules →
• Sacramento, CAPermits, zoning & local rules →

Towns, villages & rural counties

Permit checklist for building in towns & counties across California

Requirements differ town by town. Use this checklist with your local building, zoning and health departments, and include what you learn in your design instructions. We'll draw to it.

1. 01Find who issues permitsIncorporated towns and cities usually have a building department. In unincorporated areas it's the county building or planning office, or a state agency, or in some rural areas nobody. Call before you buy the lot.
2. 02Zoning & setbacksCheck the zoning district for minimum lot size, front, side and rear setbacks, maximum height, lot coverage and whether barndominiums, ADUs or metal buildings are allowed.
3. 03HOA & deed restrictionsSubdivisions often restrict minimum square footage, exterior materials, roof pitch, garage orientation and outbuildings. These can be stricter than the town code.
4. 04Septic & well permitsWithout city sewer or water, you'll need a percolation (perc) test and a septic permit from the county health department, plus a well permit.
5. 05Driveway & culvert permitConnecting to a public road usually needs a driveway or culvert permit from the town, county or state DOT.
6. 06Floodplain development permitIf any part of the lot is in a FEMA flood zone, you'll need a floodplain permit and an elevation certificate, and the lowest floor must be at or above the Base Flood Elevation plus any local freeboard.
7. 07Energy code complianceMost jurisdictions require an energy compliance report (REScheck or similar) showing insulation, windows and HVAC meet the adopted energy code.
8. 08Engineering stampMany building officials require a licensed engineer's seal for foundations, beams, trusses, or high wind, snow or seismic zones. Add our Engineer Stamp option at checkout.
9. 09Utility & fire accessRural lots may need a fire-apparatus access road, a water supply for firefighting, or wildfire (WUI) defensible-space and ignition-resistant materials.
10. 10Inspections scheduleA typical sequence is footing, foundation, framing, rough MEP, insulation and final. A certificate of occupancy is issued after final inspection.

Popular house styles in California

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Modern Plans in California

Clean lines, flat or shed roofs, floor-to-ceiling glass and indoor-outdoor living.

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Mediterranean Plans in California

Stucco walls, clay tile roofs, arches and shaded courtyards.

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Contemporary Plans in California

Bold massing, mixed cladding and bright, loft-like spaces.

Want something else? Browse all 12 home styles.

Delivery options for California clients