57 Bosque Ave
Fairfax 94930 · Unincorporated Fairfax · Unincorporated Marin · Coordinates: 37.97256, -122.61416
Executive Verdict · Public-Records Synthesis
Zoned R1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,529,000 ($1,346,000–$1,712,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 63,598 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$132,000 contributory est.)
Public building records show issued construction/renovation work on this parcel (8 total permits, latest Jun 10, 2022).
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 (State 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 Apr 1, 2024)
- ! 4 slow or stalled nearby projects within ½ mile
Closest lead: Demolition at 2 Mora Ave (340 ft N, 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 (~$18,034/yr at $1,529,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,503/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:
- 63,598 sq ft (1.46 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 57 BOSQUE AVE
Zoning & Land Use
R1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1, a single-family residential zone. The lot is 63,598 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate Fire Hazard Severity Zone (State Responsibility Area) (all of the lot, map Apr 1, 2024)
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0451E, effective March 17, 2014
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,346,000 – $1,712,000 · Status: Off market
HUD Small Area FMR (ZIP 94930) · FY 2026
Studio $2,230 · 1BR $2,680 · 2BR $3,240 · 3BR $4,140 · 4BR $4,290
Developments Deserving Closer Investigation & Active Area Builders
- Demolition at 2 Mora Ave (Issued)340 ft N
Active in "Issued" for 4.6 yr (first record Apr 26, 2022) with no new permit activity recorded in 4.5 yr.
- New home at 740 Bolinas Rd (Issued)0.41 mi E
Active in "Issued" for 2.6 yr (first record Apr 12, 2024) with no new permit activity recorded in 2.6 yr.
- New home (Issued)0.41 mi NE
Active in "Issued" for 6.3 yr (first record Jul 16, 2020) with no new permit activity recorded in 6.3 yr.
- Accessory dwelling unit at 45 Bosque Ave (Issued)410 ft SE
Active in "Issued" for 2.3 yr (first record Jul 31, 2024) with no new permit activity recorded in 6 mo.
Entity-resolved builders & contractors in ½ mile: Owner Builder (4 on parcel, 10 in ½ mi · Remodel / interior alteration); Owner (2 on parcel, 2 in ½ mi · Addition (adds square footage)); Arb (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Auto Charge Electric (1 on parcel, 1 in ½ mi · Electrical / panel); Morgan Key Hammon Construction (2 in ½ mi · Accessory dwelling unit (new or conversion)).
Permit & Project History on This Parcel (8 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 171636 | Windows / doors / siding | Issued | Iss. Jun 10, 2022 | $4,000 | New Deck At Lower Bedroom & Replace (E) Single Door With French Door |
| 155531 | General repair | Issued | Iss. May 23, 2017 | $10,000 | Upper Ret Wall |
| 155530 | General repair | Issued | Iss. May 23, 2017 | $6,000 | Lower Ret Wall***Expired |
| 153584 | New garage / accessory structure | Issued | Iss. Oct 20, 2016 | $50,000 | New Gar; Demo Carport***Ext To 10/20/19 Pd Under 153583 |
| 153583 | Addition (adds square footage) | Issued | Iss. Oct 20, 2016 | $675,000 |