121 Main Dr
San Rafael 94901 · Bayside Acres · Unincorporated Marin · Coordinates: 37.98245, -122.48122
Executive Verdict · Public-Records Synthesis
Zoned R1-B4 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 $1,712,000 ($1,507,000–$1,917,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B4 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 30,753 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ 3 documented municipal building permits on file
On-parcel permit history is indexed through May 27, 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
- ! 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: New home (0.33 mi N, entitled). 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 (~$20,138/yr at $1,712,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,678/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:
- 30,753 sq ft (0.71 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 121 MAIN DR
Zoning & Land Use
R1-B4 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B4 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B4, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B4, a single-family residential zone. The lot is 30,753 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 06041C0476E, 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: $1,507,000 – $1,917,000 · Status: Off market
HUD Small Area FMR (ZIP 94901) · FY 2026
Studio $2,150 · 1BR $2,580 · 2BR $3,120 · 3BR $3,990 · 4BR $4,130
Developments Deserving Closer Investigation & Active Area Builders
- New home (Entitled)0.33 mi N
In "Entitled" for 7.8 yr (since Jan 14, 2019), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 771 Pt San Pedro Rd (Applied)0.42 mi SE
In "Applied" for 4 yr (since Nov 15, 2022), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home (Entitled)0.43 mi NE
In "Entitled" for 5.3 yr (since Jul 12, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home (Entitled)0.45 mi SW
In "Entitled" for 8.2 yr (since Aug 28, 2018), 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: Owner Builder (1 on parcel, 11 in ½ mi · Remodel / interior alteration); Cap (1 on parcel, 1 in ½ mi · Roof replacement); Peter Levi Plumbing (1 on parcel, 1 in ½ mi · HVAC / heat pump); Owner (5 in ½ mi · Remodel / interior alteration); Dream Home Building (2 in ½ mi · New garage / accessory structure).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B42531 | Roof replacement | Issued | Iss. May 27, 2025 | $17,500 | 35 squares tear off reroof comp shingles, synthetic underlayment, new sheathing as needed, i attached garage 1 detached … |
| B32960 | HVAC / heat pump | Issued | Iss. Mar 13, 2023 | $12,000 | C/O 14 runs of ducts; 7 runs in attic, 7 runs in crawlspace — Replace Ductwork |
| 148766 | Electrical / panel | Issued | Iss. Sep 3, 2015 | $1,500 | Remove And Replace 200a Service |