23 Mt Muir Ct
San Rafael 94903 · Lucas Valley · Unincorporated Marin · Coordinates: 38.02766, -122.57363
Executive Verdict · Public-Records Synthesis
Zoned R1-B-LV in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood / CAL FIRE high fire hazard severity zone (local responsibility area) due diligence; benchmark value $1,388,000 ($1,221,000–$1,555,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone R1-B-LV allows residential use qualifying for ministerial ADU review under state law (1 ADU permit permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$5,440 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Feb 4, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 2% 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 High 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 (0.34 mi E, 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 (~$16,412/yr at $1,388,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,368/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:
- 8,233 sq ft (0.19 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 23 MT MUIR CT
Zoning & Land Use
R1-B-LV — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B-LV (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotPossible, with conditions
Zoned R1-B-LV, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 2% 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-B-LV, a single-family residential zone. The lot is 8,233 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 2% 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
- High Fire Hazard Severity Zone (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 2% of the lot); Zone X: minimal flood hazard (about 98% of the lot) · FIRM panel 06041C0289D, 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: $1,221,000 – $1,555,000 · 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 (Entitled)0.34 mi E
In "Entitled" for 2.9 yr (since Dec 7, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home (Entitled)0.34 mi E
In "Entitled" for 3.3 yr (since Jul 10, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home (Entitled)0.34 mi E
In "Entitled" for 3.8 yr (since Jan 14, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home (Entitled)0.34 mi E
In "Entitled" for 5.1 yr (since Sep 23, 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: Simply Solar (1 on parcel, 1 in ½ mi · Other); Moore Services (1 on parcel, 1 in ½ mi · HVAC / heat pump); Moore Heating Air And Solar (1 on parcel, 1 in ½ mi · Solar / battery storage); Peter Levi Plumbing (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Moore Solar Heating Cooling (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B45759 | Other | Issued | Iss. Feb 4, 2026 | $22,750 | — |
| B17440 | Plumbing / water heater / sewer | Issued | Iss. Apr 8, 2019 | $3,676 | REPLACE WATER HEATER — Replace Plumbing Fixtures(s) |
| B16446 | HVAC / heat pump | Issued | Iss. Nov 13, 2018 | $9,200 | Replace AC and Furnace — Replace Mechanical Appliance |
| 159857 | Solar / battery storage | Issued | Iss. Oct 15, 2018 | $7,200 | Rooftop Solar 5.76 K W - Express |
| 147464 | HVAC / heat pump | Issued | Iss. Jun 9, 2015 | $2,500 |