21 Calle Del Onda
Stinson Beach 94970 · Stinson Beach · Unincorporated Marin · Coordinates: 37.89905, -122.64489
Executive Verdict · Public-Records Synthesis
Zoned C-R2 in Unincorporated Marin and mapped FEMA AO flood / CAL FIRE very high fire hazard severity zone (local responsibility area) due diligence; benchmark value $3,178,000 ($2,797,000–$3,559,000).
Upsides & Opportunities
- ✓ 1 documented municipal building permit on file
On-parcel permit history is indexed through Jun 3, 2026, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AO, about 24% of the lot of lot)
Zone AO: 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 Very High Fire Hazard Severity Zone (Local Responsibility Area) (all 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 Mar 24, 2025)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 25 Lincoln Ave (0.28 mi E, 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 (~$36,997/yr at $3,178,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$3,083/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:
- 15,769 sq ft (0.36 ac)
- Assessor use:
- Single-Resid. - Unimproved
- Addresses on lot:
- 21 CALLE DEL ONDA
Zoning & Land Use
C-R2 — Residential Two Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADUPossible, with conditions
Zoned C-R2 (two-family residential): state law allows ADUs where homes are allowed. The assessor lists the lot as vacant: an ADU needs an existing or proposed main home. Very High Fire Hazard Severity Zone covers all of the lot: cities may limit ADUs here for fire safety and evacuation.
- SB 9: two homes on the lotCan't tell
Zoned C-R2 (two-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential Two Family.
- SB 9: split into two lotsCan't tell
Zoned C-R2 (two-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential Two Family.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Very High Fire Hazard Severity Zone (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone AO: 1% annual chance flood (Special Flood Hazard Area) (about 24% of the lot); Zone VE: 1% annual chance flood (Special Flood Hazard Area) (about 76% of the lot) · FIRM panel 06041C0444E, 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: $2,797,000 – $3,559,000 · 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 25 Lincoln Ave (Issued)0.28 mi E
Active in "Issued" for 7.3 yr (first record Jul 22, 2019) with no new permit activity recorded in 7.1 yr. High-impact scale (1 housing unit, $969,000 declared valuation across 1 permit).
- Mixed-use development at 3466 State Route 1 & (Issued)0.32 mi E
Active in "Issued" for 6.1 yr (first record Sep 23, 2020) with no new permit activity recorded in 5.1 yr. High-impact scale (1 housing unit, $1,000,000 declared valuation across 2 permits).
- New home at 7 Jose Patio (Issued)0.34 mi NW
Active in "Issued" for 3.5 yr (first record May 16, 2023) with no new permit activity recorded in 2.4 yr. High-impact scale (1 housing unit, $1,750,000 declared valuation across 1 permit).
- Accessory dwelling unit at 260 Belvedere Ave (Issued)0.34 mi NE
Active in "Issued" for 4.9 yr (first record Dec 16, 2021) with no new permit activity recorded in 22 mo. High-impact scale (1 housing unit, $2,000,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Owner Builder (1 on parcel, 17 in ½ mi · Commercial tenant improvement); Owner (8 in ½ mi · New garage / accessory structure); Gubbins Building (6 in ½ mi · New garage / accessory structure); George T Flynn Construction (4 in ½ mi · New garage / accessory structure); Tim Trumbo (3 in ½ mi · Addition (adds square footage)).
Permit & Project History on This Parcel (1 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181797 | New single-family home | Issued | Iss. Jun 3, 2026 | $214,708 | New S F D; Decks |