25 Rubicon Ct
San Rafael 94903 · Lucas Valley · Unincorporated Marin · Coordinates: 38.03499, -122.58337
Executive Verdict · Public-Records Synthesis
Zoned R1-B-LV in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (local responsibility area) due diligence; benchmark value $1,373,000 ($1,208,000–$1,538,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B-LV supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 6,795 sq ft lot. Local precedent is active with 2 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$10,358 contributory est.)
Public building records show issued construction/renovation work on this parcel (7 total permits, latest Aug 19, 2025).
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 (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: Accessory dwelling unit at 42 Oak Mountain Ct (0.12 mi SE, 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 (~$16,240/yr at $1,373,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,353/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:
- 6,795 sq ft (0.16 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 25 RUBICON 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 lotLikely eligible
Zoned R1-B-LV, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B-LV, a single-family residential zone. The lot is 6,795 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 (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 06041C0287D, 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: $1,208,000 – $1,538,000 · 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
- Accessory dwelling unit at 42 Oak Mountain Ct (Applied)0.12 mi SE
In "Applied" for 5.5 yr (since Apr 30, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 2000 Lucas Valley Rd (Applied)0.19 mi S
In "Applied" for 4.4 yr (since Jun 7, 2022), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
- Accessory dwelling unit at 1 Golden Lily Pl (Applied)0.22 mi W
In "Applied" for 4.8 yr (since Jan 20, 2022), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 11 Mt Burney Ct (adu 11a) (Issued)240 ft SW
Active in "Issued" for 3.3 yr (first record Jul 19, 2023) with no new permit activity recorded in 2.5 yr.
Entity-resolved builders & contractors in ½ mile: Rmd Builders (4 on parcel, 4 in ½ mi · Windows / doors / siding); Sonomarin Solar_inc (1 on parcel, 1 in ½ mi · Solar / battery storage); Cricket Roofing Services (1 on parcel, 1 in ½ mi · Roof replacement); Gene Burch Plumbing (1 on parcel, 1 in ½ mi · HVAC / heat pump); Owner Builder (20 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (7 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B43517 | Roof replacement | Issued | Iss. Aug 19, 2025 | $2,500 | Remove old existing wiring on roof.Install with new romex to existing switches,lights, and receptacles as needed. Replac… |
| B43498 | Windows / doors / siding | Issued | Iss. Aug 15, 2025 | $2,000 | Install (2) new windows to code for bedrooms Egress — Non-structural Door/Window Replacement |
| B43379 | Solar / battery storage | Issued | Iss. Aug 7, 2025 | $23,978 | Photovoltaic - Residential Flush Roof Mount, Grid Tied ESS Installation with Enphase IQ10C ESS Unit |
| B43245 | Roof replacement | Issued | Iss. Jul 28, 2025 | $16,000 | Tear off two layers of roofing and install a foam roof system — ReRoofing; With Electronic Inspection |
| B43117 |