427 Los Cerros Dr
Greenbrae 94904 · Kentfield · Unincorporated Marin · Coordinates: 37.95349, -122.53253
Executive Verdict · Public-Records Synthesis
Zoned R1-B2 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE moderate fire hazard severity zone (local responsibility area) due diligence; benchmark value $2,613,000 ($2,299,000–$2,927,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B2 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 38,028 sq ft lot. Local precedent is active with 4 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$144,000 contributory est.)
Public building records show issued construction/renovation work on this parcel (8 total permits, latest Oct 15, 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 (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: Accessory dwelling unit at 34 Wolfe Grade (0.21 mi NW, 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)
- ! Year 1 Prop 13 tax reset (~$30,500/yr at $2,613,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,542/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:
- 38,028 sq ft (0.87 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 427 LOS CERROS DR
Zoning & Land Use
R1-B2 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B2, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B2, a single-family residential zone. The lot is 38,028 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 (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 06041C0458F, effective March 16, 2016
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $2,299,000 – $2,927,000 · 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 34 Wolfe Grade (Applied)0.21 mi NW
In "Applied" for 2.8 yr (since Jan 17, 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, $750,000 declared valuation across 1 permit).
- New commercial building at 675 Sir Francis Drake Blvd (Issued)0.3 mi SW
Active in "Issued" for 12.7 yr (first record Mar 6, 2014) with no new permit activity recorded in 12.5 yr. High-impact scale ($2,400,000 declared valuation across 2 permits).
- New home at 33 Bretano Way (Issued)0.4 mi SE
Active in "Issued" for 19 mo (first record Apr 11, 2025) with no new permit activity recorded in 14 mo. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- New home at 29 Mann Dr (Issued)0.43 mi NW
Active in "Issued" for 12.7 yr (first record Mar 6, 2014) with no new permit activity recorded in 12.4 yr. High-impact scale (1 housing unit, $1,030,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Green Bay Remodeling (2 on parcel, 3 in ½ mi · Addition (adds square footage)); Rich Armusewicz Construction (1 on parcel, 3 in ½ mi · Remodel / interior alteration); Elevated Comfort (3 on parcel, 3 in ½ mi · HVAC / heat pump); Indaspec (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Ernest Ongaro And Sons (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (8 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B44366 | HVAC / heat pump | Issued | Iss. Oct 15, 2025 | $14,000 | INSTALL DUCTLESS MINI SPLIT — Mechanical Appliance |
| 178815 | Addition (adds square footage) | Issued | Iss. Mar 12, 2025 | $200,000 | Office And Master Bathrm Addition |
| B41248 | HVAC / heat pump | Issued | Iss. Feb 14, 2025 | $15,000 | REPLACE FURNACE AND DUCTS — Replace Ductwork, Replace Mechanical Appliance |
| B33902 | HVAC / heat pump | Issued | Iss. May 17, 2023 | $18,000 | ADD NEW DUCTLESS MINI SPLIT SYSTEM — Mechanical Appliance |
| B27873 | Plumbing / water heater / sewer | Issued | Iss. Nov 23, 2021 |