Building Permits in San Marino, CA

A small accessory concrete slab (walkway, patio pad, small equipment pad) of 200 square feet or less at grade is exempt from a building permit. Larger slabs that will support a future structure or are part of a building foundation fall under the building permit. Stormwater BMPs may apply per CALGreen and local LID requirements for impervious surfaces over a threshold.

A freestanding deck not more than 30 inches above grade and not more than 200 square feet is exempt from a building permit under 2025 CRC R105.2. City of San Marino zoning setbacks still apply (strict FAR limits in residential zones; verify with Building & Safety at (626) 300-0700). VHFHSZ may apply to specific hillside parcels per state mapping (verify via CAL FIRE map); on those parcels, Chapter 7A ignition-resistant materials may apply to deck materials and the 5-ft ember zone.

Fences 7 feet or less are exempt from a building permit under 2025 CRC R105.2. City of San Marino zoning regulates fence height (typically lower front-yard limits and 6 feet rear/side; historic preservation review may apply to street-facing fences on designated properties). VHFHSZ may apply to specific hillside parcels per state mapping (verify via CAL FIRE map); on those parcels, defensible space rules under PRC 4291 + AB 3074 may restrict combustible fences within 5 feet of structures (use non-combustible material in the ember zone).

An at-grade uncovered concrete or paver patio is exempt from a building permit. Adding a cover, roof, or screen enclosure turns the covered area into an accessory structure requiring a building permit. CALGreen and City of San Marino zoning may regulate impervious surface coverage and stormwater runoff.

A retaining wall 4 feet or less measured from bottom of footing to top of wall, without surcharge, is exempt from a building permit under 2025 CRC R105.2. Drainage and erosion control remain the owner's responsibility. Seismic zone (SDC D near the Raymond and Sierra Madre faults) and hillside terrain on some San Marino parcels require careful drainage design.