473 A Panoramic Hwy
Mill Valley 94941 · Muir Woods Park · Unincorporated Marin · Coordinates: 37.89985, -122.56572
Executive Verdict · Public-Records Synthesis
Zoned R1-B3 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 $2,486,000 ($2,188,000–$2,784,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B3 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 13,504 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$301,560 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Nov 19, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! Mapped flood awareness zone (Zone D: possible but undetermined flood hazard)
about 90% of the lot of the parcel intersects Zone D: possible but undetermined 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 65 Ridge Ave (0.18 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 (~$29,039/yr at $2,486,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,420/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:
- 13,504 sq ft (0.31 ac)
- Assessor use:
- Multiple-Resid. - Improved
- Addresses on lot:
- 473A PANORAMIC HWY; 473 PANORAMIC HWY
Zoning & Land Use
R1-B3 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B3 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B3, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B3, a single-family residential zone. The lot is 13,504 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 D: possible but undetermined flood hazard (about 90% of the lot); Zone X: minimal flood hazard (about 10% 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: $2,188,000 – $2,784,000 · 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 65 Ridge Ave (Applied)0.18 mi SE
In "Applied" for 4 yr (since Oct 27, 2022), 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, $3,000,000 declared valuation across 1 permit).
- New home at 526 Panoramic Hwy (Issued)0.19 mi NW
Active in "Issued" for 4.6 yr (first record Apr 21, 2022) with no new permit activity recorded in 2.1 yr. High-impact scale (1 housing unit, $1,329,450 declared valuation across 2 permits).
- New home at 49 Ridge Ave (Applied)0.13 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).
- Demolition at 688 Sequoia Valley Rd (Applied)0.41 mi E
In "Applied" for 3.2 yr (since Sep 6, 2023), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
Entity-resolved builders & contractors in ½ mile: Owner Builder (1 on parcel, 31 in ½ mi · Remodel / interior alteration); Solarcity (1 on parcel, 1 in ½ mi · Solar / battery storage); Cal Bay Service (1 on parcel, 1 in ½ mi · HVAC / heat pump); Tesla Energy (1 on parcel, 1 in ½ mi · Solar / battery storage); Owner (11 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (5 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 180534 | Accessory dwelling unit (new or conversion) | Issued | Iss. Nov 19, 2025 | — | [A B 2533] - Legalization Of Attached Adu |
| B28215 | HVAC / heat pump | Issued | Iss. Dec 30, 2021 | $29,588 | INSTALL NEW HEAT PUMP, AIR HANDLER, DUCTING, AND 2 DUCTLESS MINI SPLITS. SEER 14, HSPF 8 — New Ductwork, Mechanical Appl… |
| 167012 | Remodel / interior alteration | Issued | Iss. Jan 29, 2021 | $105,000 | Remodel Kitchen And 4 Baths- Bwop T.D. 1-5-21 |
| 162007 | Solar / battery storage | Issued | Iss. Jul 9, 2019 | $14,000 |