309 Crown Rd
Kentfield 94904 · Kentfield · Unincorporated Marin · Coordinates: 37.94440, -122.56601
Executive Verdict · Public-Records Synthesis
Zoned RSP-1 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 $2,596,000 ($2,284,000–$2,908,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RSP-1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 39,988 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 (+$127,500 contributory est.)
Public building records show issued construction/renovation work on this parcel (10 total permits, latest Feb 20, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Kentfield
104 substantial renovation & housing permits over 24 months (41.3 per 1,000 parcels vs. 16.4 citywide baseline) (#7 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Kentfield)
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)
- ! Delayed or open permit activity on this parcel
New garage / accessory structure (81363): Pending in review for 8.8 yr (19.6× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 5 slow or stalled nearby projects within ½ mile
Closest lead: Accessory dwelling unit at 432 Woodland Rd (0.45 mi N, applied). Inspect timeline history before assuming near-term completion.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · HCD APR (½-mile radius)
Parcel & Assessor
- Lot size:
- 39,988 sq ft (0.92 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 309 CROWN RD
Zoning & Land Use
RSP-1 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-1, a single-family residential zone. The lot is 39,988 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 06041C0454E, 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: $2,284,000 – $2,908,000 · Status: Off market
HUD Small Area FMR (ZIP 94904) · FY 2026
Studio $2,260 · 1BR $2,710 · 2BR $3,280 · 3BR $4,190 · 4BR $4,340
Developments Deserving Closer Investigation & Active Area Builders
- Accessory dwelling unit at 432 Woodland Rd (Applied)0.45 mi N
In "Applied" for 2.6 yr (since Apr 12, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). High-impact scale (1 housing unit, $1,250,000 declared valuation across 1 permit).
- New garage / accessory structure (81363) (Applied)On this parcel
Pending in review for 8.8 yr (19.6× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
- New home at 6 Turnagain Rd (Issued)0.49 mi NE
Active in "Issued" for 9.3 yr (first record Aug 3, 2017) with no new permit activity recorded in 9.1 yr. High-impact scale (1 housing unit, $1,196,000 declared valuation across 1 permit).
- New home (Entitled)0.27 mi SE
In "Entitled" for 5.7 yr (since Feb 22, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
Entity-resolved builders & contractors in ½ mile: Owner (1 on parcel, 5 in ½ mi · Addition (adds square footage)); Ernest Ongaro And Sons (2 on parcel, 2 in ½ mi · Other); Moore Services (2 on parcel, 2 in ½ mi · HVAC / heat pump); Alliance Plumbing (2 on parcel, 2 in ½ mi · Plumbing / water heater / sewer); Slm Builders (1 on parcel, 1 in ½ mi · New garage / accessory structure).
Permit & Project History on This Parcel (10 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B41334 | Plumbing / water heater / sewer | Issued | Iss. Feb 20, 2025 | $2,100 | Replace tankless water heater using existing connections — Replace Plumbing Fixtures(s) |
| B34672 | Roof replacement | Issued | Iss. Jul 13, 2023 | $10,800 | tear off of existing roof and installation of new shingle roof — ReRoofing |
| B25785 | HVAC / heat pump | Issued | Iss. May 19, 2021 | $1,800 | INSTALLING 5 RUNS OF R6 ALUMAFLEX DUCTING — Replace Ductwork, Replace Mechanical Appliance |
| B23570 | HVAC / heat pump | Issued | Iss. Sep 15, 2020 | $4,250 | ADD ON 3 TON A/C TO THE RIGHT SIDE YARD — Replace Mechanical Appliance |
| B20706 | Other | Issued |