257 Seadrift Rd
Stinson Beach 94970 · Stinson Beach · Unincorporated Marin · Coordinates: 37.90737, -122.66810
Executive Verdict · Public-Records Synthesis
Zoned C-RSPS-1.4 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA A flood due diligence; benchmark value $3,022,000 ($2,659,000–$3,385,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone C-RSPS-1.4 allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$17,694 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Jun 24, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (A, about 10% of the lot of lot)
Zone A: 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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 252 Seadrift Rd (360 ft SE, issued). Inspect timeline history before assuming near-term completion.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · HCD APR (½-mile radius)
- ! Year 1 Prop 13 tax reset (~$35,203/yr at $3,022,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,934/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:
- 7,536 sq ft (0.17 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 257 SEADRIFT RD
Zoning & Land Use
C-RSPS-1.4 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned C-RSPS-1.4 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotPossible, with conditions
Zoned C-RSPS-1.4, a single-family residential zone. FEMA Special Flood Hazard Area (Zone A) covers about 10% 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-RSPS-1.4, a single-family residential zone. The lot is 7,536 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 A) covers about 10% 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
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone A: 1% annual chance flood (Special Flood Hazard Area) (about 10% of the lot); Zone X: 0.2% annual chance flood hazard (shaded X) (about 90% of the lot) · FIRM panel 06041C0441E, 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: $2,659,000 – $3,385,000 · Status: Off market
HUD Small Area FMR (ZIP 94970) · FY 2026
Studio $2,090 · 1BR $2,510 · 2BR $3,030 · 3BR $3,870 · 4BR $4,010
Developments Deserving Closer Investigation & Active Area Builders
- New home at 252 Seadrift Rd (Issued)360 ft SE
Active in "Issued" for 9.2 yr (first record Sep 5, 2017) with no new permit activity recorded in 8.9 yr. High-impact scale (1 housing unit, $1,600,000 declared valuation across 1 permit).
- New home at 177 Dipsea Rd (Issued)390 ft NW
Active in "Issued" for 12.8 yr (first record Jan 16, 2014) with no new permit activity recorded in 12.3 yr. High-impact scale (1 housing unit, $1,452,000 declared valuation across 1 permit).
- New home at 285 Seadrift Rd (Issued)0.16 mi W
Active in "Issued" for 9.4 yr (first record Jun 12, 2017) with no new permit activity recorded in 9 yr. High-impact scale (1 housing unit, $900,000 declared valuation across 1 permit).
- New home at 228 Seadrift Rd (Issued)0.18 mi E
Active in "Issued" for 6.9 yr (first record Dec 30, 2019) with no new permit activity recorded in 4.4 yr. High-impact scale (1 housing unit, $2,500,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Ernest Ongaro And Sons (3 on parcel, 3 in ½ mi · HVAC / heat pump); Solarsesame (1 on parcel, 1 in ½ mi · Solar / battery storage); Gubbins Building (15 in ½ mi · Remodel / interior alteration); Peterson Construction And Development (10 in ½ mi · New single-family home); Kasten Builders (9 in ½ mi · New single-family home).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B47275 | Plumbing / water heater / sewer | Issued | Iss. Jun 24, 2026 | $21,454 | Replace Plumbing Fixtures(s) |
| B42977 | HVAC / heat pump | Issued | Iss. Jul 3, 2025 | $23,877 | Installation of 5 Ton Mitsubishi Mini Split System on left side yard — Mechanical Appliance |
| B42410 | Solar / battery storage | Issued | Iss. May 14, 2025 | $23,922 | Rooftop 14 panel solar system with 2 batteries and 200A System controller |
| B40544 | Solar / battery storage | Issued | Iss. Dec 13, 2024 | $5,000 | SYSTEM SIZE: 6.150kW DC / 5.966kW AC SYSTEM SIZE PV MODULE: (15) HANWHA Q.PEAK DUO BLK ML-G10+415 INVERTER: (15) ENPHASE… |