56 Sylvestris Dr
San Geronimo 94963 · San Geronimo Village · Unincorporated Marin · Coordinates: 38.01159, -122.66645
Executive Verdict · Public-Records Synthesis
Zoned R1-B4-SGV in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,304,000 ($1,148,000–$1,460,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B4-SGV supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 10,803 sq ft lot. Local precedent is active with 3 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$6,624 contributory est.)
Public building records show issued construction/renovation work on this parcel (3 total permits, latest Apr 23, 2026).
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 High 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: New home at 15 Fir Ave (0.48 mi W, 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 (~$15,446/yr at $1,304,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,287/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:
- 10,803 sq ft (0.25 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 56 SYLVESTRIS DR
Zoning & Land Use
R1-B4-SGV — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B4-SGV (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B4-SGV, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B4-SGV, a single-family residential zone. The lot is 10,803 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
- High 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 06041C0275D, effective May 4, 2009
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,148,000 – $1,460,000 · Status: Off market
HUD Small Area FMR (ZIP 94963) · FY 2026
Studio $2,500 · 1BR $3,000 · 2BR $3,630 · 3BR $4,630 · 4BR $4,800
Developments Deserving Closer Investigation & Active Area Builders
- New home at 15 Fir Ave (Applied)0.48 mi W
In "Applied" for 5 yr (since Nov 1, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 625 San Geronimo Valley Dr (Issued)0.19 mi N
Active in "Issued" for 4.9 yr (first record Dec 6, 2021) with no new permit activity recorded in 3.9 yr.
- Accessory dwelling unit at 320 Meadow Way (Applied)0.14 mi NW
In "Applied" for 22 mo (since Jan 9, 2025), exceeding the 253d median and 456d 75th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 15 Fir Ave (Issued)0.48 mi W
Active in "Issued" for 10.3 yr (first record Aug 3, 2016) with no new permit activity recorded in 10.2 yr.
Entity-resolved builders & contractors in ½ mile: Freedom Forever (1 on parcel, 1 in ½ mi · Solar / battery storage); Goldline Roofing And Renovation (1 on parcel, 1 in ½ mi · Roof replacement); West Coast Solar (1 on parcel, 1 in ½ mi · Other); Owner Builder (7 in ½ mi · Demolition); Bitzer (2 in ½ mi · Addition (adds square footage)).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B46582 | Other | Issued | Iss. Apr 23, 2026 | $2,200 | — |
| B46573 | Roof replacement | Issued | Iss. Apr 22, 2026 | $8,000 | ReRoofing |
| 155843 | Solar / battery storage | Issued | Iss. Jun 27, 2017 | $23,000 | 6.60kw Roof Mount Photovoltaic - Express |