1125 W California Ave
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.88876, -122.54236
Executive Verdict · Public-Records Synthesis
Zoned R1-B1 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 $2,288,000 ($2,013,000–$2,563,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 10,934 sq ft lot. Local precedent is active with 10 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$120,200 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Apr 2, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Tamalpais
50 substantial renovation & housing permits over 24 months (20.5 per 1,000 parcels vs. 16.4 citywide baseline) (#3 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Tamalpais)
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 560 Alta Way (0.24 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 (~$26,762/yr at $2,288,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,230/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:
- 10,934 sq ft (0.25 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 1125 W CALIFORNIA AVE
Zoning & Land Use
R1-B1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B1, a single-family residential zone. The lot is 10,934 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 06041C0468F, 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: $2,013,000 – $2,563,000 · Status: Off market
HUD Small Area FMR (ZIP 94941) · FY 2026
Studio $2,730 · 1BR $3,270 · 2BR $3,960 · 3BR $5,060 · 4BR $5,240
Developments Deserving Closer Investigation & Active Area Builders
- New home at 560 Alta Way (Applied)0.24 mi SE
In "Applied" for 3.3 yr (since Aug 10, 2023), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). High-impact scale (1 housing unit, $975,000 declared valuation across 1 permit).
- New home at 210 Brabo Ter (Issued)0.31 mi N
Active in "Issued" for 3.1 yr (first record Oct 12, 2023) with no new permit activity recorded in 2.6 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
- New home at 204 Reed St (Issued)0.34 mi N
Active in "Issued" for 4.3 yr (first record Aug 5, 2022) with no new permit activity recorded in 3.5 yr. High-impact scale (1 housing unit, $950,000 declared valuation across 1 permit).
- New home at 164 Linden Ln (Issued)0.4 mi N
Active in "Issued" for 8.1 yr (first record Oct 1, 2018) with no new permit activity recorded in 7.5 yr. High-impact scale (1 housing unit, $780,000 declared valuation across 3 permits).
Entity-resolved builders & contractors in ½ mile: Lamperti Contracting And Design (1 on parcel, 4 in ½ mi · Remodel / interior alteration); James Clough Enterprises (1 on parcel, 2 in ½ mi · Accessory dwelling unit (new or conversion)); Pagan Construction (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Wedge Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Arb (1 on parcel, 1 in ½ mi · Other).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B46362 | Other | Issued | Iss. Apr 2, 2026 | $3,500 | — |
| 175877 | Remodel / interior alteration | Issued | Iss. Feb 1, 2024 | $156,246 | Structural Kitchen Remodel & Relocate Windows |
| 168949 | General repair | Issued | Iss. Jul 28, 2021 | $22,750 | Repair Deck |
| B17990 | Roof replacement | Issued | Iss. Jun 13, 2019 | $28,500 | **Detached Garage with tree damage** Remove existing 8 sq ft roof down to sheathing. Prepare existing sheathing for new … |
| 158459 | Remodel / interior alteration | Issued | Iss. May 10, 2018 | $110,000 |