48 Main St
San Quentin 94964 · San Quentin · Unincorporated Marin · Coordinates: 37.94175, -122.48349
Executive Verdict · Public-Records Synthesis
Zoned RSP-5.8 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $1,305,000 ($1,109,000–$1,501,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RSP-5.8 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 2,919 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ 6 documented municipal building permits on file
On-parcel permit history is indexed through Aug 6, 2026, 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
- ! 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)
- ! 1 slow or stalled nearby project within ½ mile
Closest lead: New home at 22 Mckenzie St (70 ft N, 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 (~$15,458/yr at $1,305,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,288/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:
- 2,919 sq ft (0.07 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 48 MAIN ST
Zoning & Land Use
RSP-5.8 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-5.8 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-5.8, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-5.8, a single-family residential zone. The lot is 2,919 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
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0478E, 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: $1,109,000 – $1,501,000 · Status: Off market
HUD Small Area FMR (ZIP 94964) · FY 2026
Studio $2,530 · 1BR $3,040 · 2BR $3,680 · 3BR $4,700 · 4BR $4,870
Nearby Activity (½ mile radius, since November 2024)
0 active or recent development projects and 12 total building permits recorded within ½ mile.
- Additions & renovations2 permits
- Building systems8 permits
Developments Deserving Closer Investigation & Active Area Builders
- New home at 22 Mckenzie St (Issued)70 ft N
Active in "Issued" for 3.9 yr (first record Dec 27, 2022) with no new permit activity recorded in 2.8 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Semper Solaris Construction (2 on parcel, 2 in ½ mi · Other); Jemico (2 on parcel, 2 in ½ mi · Windows / doors / siding); Ro Heating And Air Conditioning (1 on parcel, 1 in ½ mi · Other); Charles Cole (1 on parcel, 1 in ½ mi · Electrical / panel); James Flanagan Builder (2 in ½ mi · New garage / accessory structure).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B47681 | Electrical / panel | Issued | Iss. Aug 6, 2026 | $9,500 | Service Upgrade |
| B47626 | Other | Issued | Iss. Jul 26, 2026 | $15,000 | Mechanical Appliance, Replace Mechanical Appliance |
| B47537 | Other | Issued | Iss. Jul 20, 2026 | $49,486 | — |
| B47493 | Windows / doors / siding | Issued | Iss. Jul 14, 2026 | $14,495 | Non-structural Door/Window Replacement |
| B47359 | Roof replacement | Issued | Iss. Jul 1, 2026 | $9,469 | ReRoofing |