18555 State Route 1
Marshall 94940 · East Shore · Unincorporated Marin · Coordinates: 38.14312, -122.87875
Executive Verdict · Public-Records Synthesis
Zoned C-RSP-0.33 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood / CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,618,000 ($1,424,000–$1,812,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone C-RSP-0.33 allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$7,360 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest May 31, 2024).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 44% of the lot of lot)
Zone AE: 1% annual chance flood (Special Flood Hazard Area) overlaps this parcel. Expect mandatory flood insurance for federally backed loans and floodplain elevation/mitigation rules for new units or SB 9 applications.
Source: FEMA National Flood Hazard Layer (parcel polygon)
- ! CAL FIRE Moderate Fire Hazard Severity Zone (State Responsibility Area) (about 91% of the lot of lot)
Located in a mapped Fire Hazard Severity Zone. Expect Chapter 7A ignition-resistant building standards, defensible-space inspections, and stricter property insurance underwriting.
Source: CAL FIRE FHSZ (map Apr 1, 2024)
- ! Year 1 Prop 13 tax reset (~$19,057/yr at $1,618,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,588/mo). Confirm exact Mello-Roos / CFD special assessments on the county tax bill.
Source: CA Const. Art. XIIIA (Prop 13) · County Tax Collector
Parcel & Assessor
- Lot size:
- 7,884 sq ft (0.18 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 18555 STATE ROUTE 1
Zoning & Land Use
C-RSP-0.33 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned C-RSP-0.33 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotPossible, with conditions
Zoned C-RSP-0.33, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 44% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
- SB 9: split into two lotsPossible, with conditions
Zoned C-RSP-0.33, a single-family residential zone. The lot is 7,884 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. FEMA Special Flood Hazard Area (Zone AE) covers about 44% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate Fire Hazard Severity Zone (State Responsibility Area) (about 91% of the lot, map Apr 1, 2024)
- FEMA National Flood Hazard Layer
- Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 44% of the lot); Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 32% of the lot); Zone X: minimal flood hazard (about 24% of the lot) · FIRM panel 06041C0095E, effective August 15, 2017
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,424,000 – $1,812,000 · Status: Off market
HUD Small Area FMR (ZIP 94940) · FY 2026
Studio $2,050 · 1BR $2,510 · 2BR $2,990 · 3BR $3,870 · 4BR $4,090
Developments Deserving Closer Investigation & Active Area Builders
Entity-resolved builders & contractors in ½ mile: Wedge Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Vital Energy Solutions (1 on parcel, 1 in ½ mi · Other); Gaf Energy (1 on parcel, 1 in ½ mi · Solar / battery storage); Houston Electric And Telecommunications (1 on parcel, 1 in ½ mi · Electrical / panel); Trainor Commercial Construction (4 in ½ mi · Commercial tenant improvement).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B38249 | Other | Issued | Iss. May 31, 2024 | $13,323 | Provide and install 18kW Generac generator and 200A ATS |
| B36640 | Solar / battery storage | Issued | Iss. Jan 10, 2024 | $7,500 | 3.588kW PV system, 78 modules, 1 inverter |
| B36635 | Roof replacement | Issued | Iss. Jan 9, 2024 | $32,852 | House & Detached Shed Remove existing roof down to sheathing. Prepare existing sheathing for new roof. Install GAF Timbe… |
| B11065 | Electrical / panel | Issued | Iss. Sep 26, 2016 | $3,200 | REPLACE MAIN PANEL — Service Upgrade |