10 Mountain Ln
Mill Valley 94941 · Muir Woods Park · Unincorporated Marin · Coordinates: 37.90455, -122.56923
Executive Verdict · Public-Records Synthesis
Zoned R1-B2 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 $2,065,000 ($1,817,000–$2,313,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B2 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 6,316 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$5,440 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Jul 10, 2018).
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 (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)
- ! 4 slow or stalled nearby projects within ½ mile
Closest lead: New home at 526 Panoramic Hwy (0.2 mi S, 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 (~$24,198/yr at $2,065,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,016/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:
- 6,316 sq ft (0.14 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 10 MOUNTAIN LN
Zoning & Land Use
R1-B2 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B2, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B2, a single-family residential zone. The lot is 6,316 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 06041C0465E, effective August 15, 2017
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,817,000 – $2,313,000 · 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 526 Panoramic Hwy (Issued)0.2 mi S
Active in "Issued" for 4.6 yr (first record Apr 21, 2022) with no new permit activity recorded in 2 yr. High-impact scale (1 housing unit, $1,329,450 declared valuation across 2 permits).
- New home at 49 Ridge Ave (Applied)0.48 mi S
In "Applied" for 5.1 yr (since Oct 15, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home at 120 Redwood Ave (Issued)0.13 mi SE
Active in "Issued" for 14.9 yr (first record Dec 27, 2011) with no new permit activity recorded in 11.9 yr.
- Demolition at 7 Brighton Blvd (Issued)0.36 mi SE
Active in "Issued" for 11.8 yr (first record Jan 13, 2015) with no new permit activity recorded in 11.8 yr.
Entity-resolved builders & contractors in ½ mile: Owner (3 on parcel, 11 in ½ mi · Remodel / interior alteration); Quattro Solar (1 on parcel, 1 in ½ mi · Solar / battery storage); Owner Builder (25 in ½ mi · New garage / accessory structure); Vida Building (2 in ½ mi · Remodel / interior alteration); Oxbow Pool And Landscape Contractors (1 in ½ mi · New garage / accessory structure).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 159006 | Solar / battery storage | Issued | Iss. Jul 10, 2018 | $16,000 | Solar Pv 4.8kw - Express |
| 157194 | New garage / accessory structure | Issued | Iss. Dec 6, 2017 | $250,000 | Addn; Rmdl; Repl Deck; New Gar T.D. 9/5/17 |
| B11052 | Electrical / panel | Issued | Iss. Sep 21, 2016 | $500 | DEDICATED CIRCUIT FOR SEPTIC PUMP — New Circuits / Outlets |
| 153283 | General repair | Issued | Iss. Sep 20, 2016 | $50,000 | Foundation Upgrade T.D. 6/24/16 |