51 Windstone Dr
San Rafael 94903 · Marinwood · Unincorporated Marin · Coordinates: 38.03550, -122.54326
Executive Verdict · Public-Records Synthesis
Zoned RMP-6 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE moderate fire hazard severity zone (local responsibility area) due diligence; benchmark value $1,287,000 ($1,133,000–$1,441,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-6 allows residential use qualifying for ministerial ADU review under state law (3 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$31,451 contributory est.)
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Oct 31, 2023).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! Mapped flood awareness zone (Zone X: minimal flood hazard)
all of the lot of the parcel intersects Zone X: minimal flood hazard. Outside mandatory federal SFHA insurance rules, but check local drainage and finished-floor requirements.
Source: FEMA National Flood Hazard Layer (parcel polygon)
- ! CAL FIRE Moderate 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: 125 new homes (0.21 mi NE, entitled). 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 (~$15,251/yr at $1,287,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,271/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:
- 697 sq ft (0.02 ac)
- Assessor use:
- Single Family Attached
- Addresses on lot:
- 51 WINDSTONE DR
Zoning & Land Use
RMP-6 — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-6 (multifamily residential): state law allows ADUs where homes are allowed. On a multifamily lot the state allowance is different: ADUs in non-living space of the building, plus up to eight detached ADUs.
- SB 9: two homes on the lotUnlikely
Zoned RMP-6 (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-6 (multifamily residential), not a single-family residential zone.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate Fire Hazard Severity Zone (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0291D, effective May 4, 2009
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,133,000 – $1,441,000 · Status: Off market
HUD Small Area FMR (ZIP 94903) · FY 2026
Studio $2,880 · 1BR $3,450 · 2BR $4,180 · 3BR $5,340 · 4BR $5,530
Developments Deserving Closer Investigation & Active Area Builders
- 125 new homes (Entitled)0.21 mi NE
In "Entitled" for 23 mo (since Dec 6, 2024), exceeding the 292d median and 313d 90th percentile for new multifamily / condos / mixed-use permits in Unincorporated Marin (n=21). High-impact scale (125 housing units, 124 deed-restricted affordable across 0 permits).
- New commercial building at 200 Marinwood Ave (Applied)0.18 mi SE
Active in "Applied" for 3.9 yr (first record Dec 14, 2022) with no new permit activity recorded in 3.9 yr. High-impact scale ($35,000,000 declared valuation across 2 permits).
- Accessory dwelling unit at 2558 Heatherstone Dr (Applied)330 ft NE
In "Applied" for 5.5 yr (since Apr 29, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 268 Emerystone Ter (Issued)0.11 mi E
Active in "Issued" for 19 mo (first record Apr 18, 2025) with no new permit activity recorded in 14 mo.
Entity-resolved builders & contractors in ½ mile: Owner (1 on parcel, 30 in ½ mi · Remodel / interior alteration); Sunrun Installation Services (4 on parcel, 4 in ½ mi · Electrical / panel); Bachelder Mark And Assoc (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Owner Builder (50 in ½ mi · Remodel / interior alteration); Mastec Communicaitons Group (5 in ½ mi · New multifamily / condos / mixed-use).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B35955 | Electrical / panel | Issued | Iss. Oct 31, 2023 | $2,500 | Reference: B33032 Incorrect panel installed, Correct panel: 125A Panel 225A Bus — Service Upgrade |
| B33032 | Electrical / panel | Issued | Iss. Mar 17, 2023 | $4,200 | New Mpu — Service Upgrade |
| B33031 | Solar / battery storage | Issued | Iss. Mar 17, 2023 | $11,856 | 6.00 AC (16) Panel Roof mount Pv System |
| B33030 | Roof replacement | Issued | Iss. Mar 17, 2023 | $5,292 | Tear Off and Replacement (Comp): Removal of the existing composite shingles and underlayment. Installation of new underl… |
| B22522 | Windows / doors / siding | Issued |