Corte Madera

Marin County (population ~261,000) sits directly north of San Francisco across the Golden Gate, occupying the peninsula between San Francisco Bay (east), the Pacific Ocean (west), and Sonoma County (north). The county seat is San Rafael; incorporated jurisdictions are San Rafael, Novato, Mill Valley, Larkspur, Corte Madera, Tiburon, Belvedere, Sausalito, Fairfax, San Anselmo, and Ross. Major unincorporated communities include Marin City, Strawberry, Tamalpais Valley, Kentfield, Greenbrae, Lucas Valley-Marinwood, Santa Venetia, Black Point-Green Point, Bolinas, Stinson Beach, Inverness, Point Reyes Station, Olema, Marshall, Tomales, Dillon Beach, Muir Beach, Nicasio, Lagunitas-Forest Knolls, San Geronimo, and Woodacre. The county Board of Supervisors administers ADU permitting on unincorporated parcels under California Government Code Sec. 65852.2 and 65852.22 (state ADU preemption regime). Marin is among the highest-housing-cost counties in the United States (median single-family home well above $1.5M county-wide, exceeding $2M in Belvedere/Tiburon/Ross/Mill Valley/Sausalito); ADU production has been a focal housing-policy lever, and the county runs an active ADU resource center. The county is overwhelmingly publicly-owned: the Golden Gate National Recreation Area (GGNRA), Point Reyes National Seashore, Mount Tamalpais State Park, Samuel P. Taylor State Park, Tomales Bay State Park, Marin Municipal Water District watershed lands, Marin County Open Space District preserves, and the Marin Agricultural Land Trust easements collectively cover roughly 84% of the county area.

• Marin County Development Code (Title 22), ADU/JADU provisions including Sec. 22.32.140
• Cal. Gov't Code Sec. 65852.2 (Accessory Dwelling Units)
• Cal. Gov't Code Sec. 65852.22 (Junior Accessory Dwelling Units)
• California Coastal Act (Pub. Resources Code Sec. 30000 et seq.)
• Marin County Local Coastal Program (LCP) - certified
• Marin County ADU resource program / pre-approved plans

State-floor overlay: California state ADU preemption applies in full to unincorporated parcels. Coastal-zone parcels also require Coastal Development Permits (CDPs) under the certified LCP, with Coastal Commission appeal jurisdiction on parcels in the coastal-appeal area. AB 1033 condo-conversion election status pending verification (Marin County is among the more likely to opt in given its housing-cost pressure). AB 976 prohibits owner-occupancy mandates on detached ADUs. SB 9 urban lot-split provisions apply only within incorporated cities, not in unincorporated Marin. HCD oversight: ordinance amendments submitted within 60 days per Sec. 65852.2(h). Marin's Housing Element is among the higher-RHNA-allocation jurisdictions per capita given its low historical production.

Marin County overlays of consequence: California Coastal Zone covering the entire west Marin coastline and northern Bay shoreline; CAL FIRE State Responsibility Area covering most of west Marin and Mount Tamalpais foothills with Very High FHSZ in many areas; Golden Gate National Recreation Area (GGNRA - the largest urban national park in the US, ~80,000 acres in Marin); Point Reyes National Seashore (~71,000 acres including the working pastoral zone with NPS agricultural leases); Mount Tamalpais State Park, Samuel P. Taylor State Park, Tomales Bay State Park, China Camp State Park, Olompali State Historic Park; Marin Municipal Water District watershed (~22,000 acres including Mt Tam east slope, Mt Lagunitas watershed, Phoenix/Alpine/Bon Tempe/Lagunitas/Kent reservoirs); Marin County Open Space District (~16,000 acres across 34 preserves); Marin Agricultural Land Trust easements (~58,000 acres of west Marin ag/grazing); FEMA SFHA along Bolinas Lagoon, Tomales Bay, Lagunitas Creek, Corte Madera Creek, San Rafael Creek, Bay shoreline; tsunami inundation along Pacific and northern Bay; San Andreas Fault traverses the county (Tomales Bay is the surface trace; the 1906 SF earthquake ruptured along this segment with up to 21 ft of right-lateral offset at Olema); Federated Indians of Graton Rancheria ancestral-territory tribal-consultation overlay (AB 52 / SB 18); Marin City sea-level-rise / tidal-flooding overlay; San Quentin State Prison (CDCR institutional, on the Bay shore at Point San Quentin).

• California Coastal Zone - Marin Coastside (West Marin LCP)
• CAL FIRE State Responsibility Area / Very High FHSZ - Mt Tam / West Marin
• Golden Gate NRA / Point Reyes National Seashore / Muir Woods NM
• Marin Municipal Water District Watershed (closed to private development)
• Marin County Open Space District / MALT agricultural easements
• San Andreas Fault Zone (1906 rupture; Tomales Bay surface trace)
• Tsunami Inundation Zone - Marin coast and northern Bay
• FEMA SFHA / Sea-Level-Rise overlay - Marin City, Bay edge, west Marin estuaries
• Federated Indians of Graton Rancheria - Coast Miwok ancestral-territory consultation

Marin County Community Development Agency / Planning Division issues ADU permits for unincorporated parcels including Marin City, Strawberry, Tamalpais Valley, Kentfield, Greenbrae, Lucas Valley-Marinwood, Santa Venetia, Bolinas, Stinson Beach, Inverness, Point Reyes Station, Olema, Marshall, Tomales, Dillon Beach, Muir Beach, Nicasio, Lagunitas-Forest Knolls, San Geronimo, and Woodacre. Practical permitting frictions: California Coastal Zone covers all of west Marin coastline and triggers CDP review with Coastal Commission appeal rights; CAL FIRE State Responsibility Area covers most of west Marin and the Mount Tamalpais foothills with Very High FHSZ - the 2018 Mendocino Complex / Camp Fire era reset West Marin WUI evacuation planning, and Marin's narrow canyon roads (Lucas Valley, Tamalpais Valley, San Geronimo Valley, Bolinas Lagoon access) create significant evacuation-corridor concerns; FEMA SFHA along Bolinas Lagoon, Tomales Bay shoreline, Lagunitas Creek, Corte Madera Creek, San Rafael Creek, and the Bay edge; Marin Municipal Water District watershed (~22,000 acres) is closed to private development; Point Reyes National Seashore agricultural lease zone covers ranches in the seashore; tsunami inundation along the Pacific coast and northern Bay; high housing-cost dynamics drive significant ADU activity (Marin permits hundreds of ADUs annually relative to its small total housing stock).