12 Hillside Ave
Kentfield 94904 · Kentfield · Unincorporated Marin · Coordinates: 37.95424, -122.55381
Executive Verdict · Public-Records Synthesis
Zoned R1-B2 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood / CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $2,206,000 ($1,941,000–$2,471,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone R1-B2 allows residential use qualifying for ministerial ADU review under state law (2 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$6,080 contributory est.)
Public building records show issued construction/renovation work on this parcel (2 total permits, latest Jun 12, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Kentfield
103 substantial renovation & housing permits over 24 months (40.9 per 1,000 parcels vs. 16.3 citywide baseline) (#7 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Kentfield)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 7% of the lot of lot)
Zone AE: 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 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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 75 Rock Rd (0.26 mi W, 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 (~$25,819/yr at $2,206,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,152/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:
- 5,489 sq ft (0.13 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 12 HILLSIDE AVE
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 lotPossible, with conditions
Zoned R1-B2, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 7% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
- SB 9: split into two lotsPossible, with conditions
Zoned R1-B2, a single-family residential zone. The lot is 5,489 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. FEMA Special Flood Hazard Area (Zone AE) covers about 7% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
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 AE: 1% annual chance flood (Special Flood Hazard Area) (about 7% of the lot); Zone X: minimal flood hazard (about 93% 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: $1,941,000 – $2,471,000 · 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
- New home at 75 Rock Rd (Issued)0.26 mi W
Active in "Issued" for 2.2 yr (first record Aug 27, 2024) with no new permit activity recorded in 18 mo. High-impact scale (1 housing unit, $936,400 declared valuation across 1 permit).
- Accessory dwelling unit at 625 College Ave (a D U 627) (Issued)0.35 mi SE
Active in "Issued" for 3.9 yr (first record Dec 7, 2022) with no new permit activity recorded in 3 yr. High-impact scale (1 housing unit, $4,500,000 declared valuation across 1 permit).
- Accessory dwelling unit at 31 N Ridgewood Rd (adu 31a) (Issued)0.4 mi SW
Active in "Issued" for 20 mo (first record Feb 28, 2025) with no new permit activity recorded in 16 mo. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- Accessory dwelling unit at 66 Hanken Dr (adu 66a) (Issued)0.48 mi NE
Active in "Issued" for 3.1 yr (first record Sep 29, 2023) with no new permit activity recorded in 2.8 yr. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: American Heating And Air (1 on parcel, 1 in ½ mi · HVAC / heat pump); Tesla Energy (1 on parcel, 1 in ½ mi · Solar / battery storage); Owner Builder (39 in ½ mi · Remodel / interior alteration); Owner (30 in ½ mi · Remodel / interior alteration); Swett Construction (9 in ½ mi · New garage / accessory structure).
Permit & Project History on This Parcel (2 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B42743 | HVAC / heat pump | Issued | Iss. Jun 12, 2025 | $10,372 | INSTALL CENTRAL SPLIT AC, 2 TON, 16 SEER. LOCATED ON RIGHT SIDE YARD — Mechanical Appliance |
| 164964 | Solar / battery storage | Issued | Iss. Jun 23, 2020 | $7,000 | Energy Storage System |