310 Adrian Way
San Rafael 94903 · Santa Venetia · Unincorporated Marin · Coordinates: 38.01071, -122.51909
Executive Verdict · Public-Records Synthesis
Zoned R1-B1 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood due diligence; benchmark value $1,204,000 ($1,060,000–$1,348,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone R1-B1 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
- ✓ 1 documented municipal building permit on file
On-parcel permit history is indexed through Apr 7, 2025, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 65% 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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 16 Crestview Way (0.14 mi S, 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 (~$14,296/yr at $1,204,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,191/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:
- 8,886 sq ft (0.20 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 310 ADRIAN WAY
Zoning & Land Use
R1-B1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotPossible, with conditions
Zoned R1-B1, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 65% 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-B1, a single-family residential zone. The lot is 8,886 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 65% 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
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 65% of the lot); Zone X: minimal flood hazard (about 4% of the lot); Zone X: 0.2% annual chance flood hazard (shaded X) (about 32% of the lot) · FIRM panel 06041C0294E, 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: $1,060,000 – $1,348,000 · 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
- New home at 16 Crestview Way (Issued)0.14 mi S
Active in "Issued" for 2.5 yr (first record May 20, 2024) with no new permit activity recorded in 15 mo. High-impact scale (1 housing unit, $770,000 declared valuation across 1 permit).
- Accessory dwelling unit at 106 Mabry Way (Applied)0.1 mi W
In "Applied" for 3.1 yr (since Sep 28, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 120 Mabry Way (Applied)0.15 mi W
In "Applied" for 3.1 yr (since Sep 21, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 321 N San Pedro Rd (Applied)0.24 mi S
In "Applied" for 5.8 yr (since Feb 9, 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: William Gotelli Plumbing (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Owner Builder (39 in ½ mi · Remodel / interior alteration); Owner (21 in ½ mi · Remodel / interior alteration); Lsr Maintenancellc (5 in ½ mi · Remodel / interior alteration); Gustavo Brooks Construction (4 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (1 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B41928 | Plumbing / water heater / sewer | Issued | Iss. Apr 7, 2025 | $11,000 | Replace 40 gallon natural gas tank water heater with tankless water heater — Replace Plumbing Fixtures(s) |