54 Shell Rd
Mill Valley 94941 · Alto · Unincorporated Marin · Coordinates: 37.90651, -122.52160
Parcel & Assessor
- Lot size:
- 13,765 sq ft (0.32 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 54 SHELL RD
Zoning & Land Use
RA-B2 — Residential Agriculture (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RA-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotCan't tell
Zoned RA-B2 (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
- SB 9: split into two lotsCan't tell
Zoned RA-B2 (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone AO: 1% annual chance flood (Special Flood Hazard Area) (about 45% of the lot); Zone X: minimal flood hazard (about 55% of the lot) · FIRM panel 06041C0467F, 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: $1,944,000 – $2,474,000 · 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 30 Shell Rd (Issued)0.16 mi E
Active in "Issued" for 2.3 yr (first record Jul 5, 2024) with no new permit activity recorded in 22 mo. High-impact scale (1 housing unit, $2,800,000 declared valuation across 1 permit).
- Accessory dwelling unit at 55 Plaza Dr (adu 55a) (Issued)0.25 mi SE
Active in "Issued" for 2.5 yr (first record Apr 17, 2024) with no new permit activity recorded in 19 mo. High-impact scale (1 housing unit, $790,000 declared valuation across 1 permit).
- New home at 57 Shell Rd (Issued)180 ft S
Active in "Issued" for 10.4 yr (first record May 25, 2016) with no new permit activity recorded in 10.1 yr.
- New home at 64 Shell Rd (Issued)370 ft W
Active in "Issued" for 12.9 yr (first record Dec 19, 2013) with no new permit activity recorded in 12.5 yr.
Permit & Project History on This Parcel (4 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 94576 | Accessory dwelling unit (new or conversion) | Applied | App. Oct 15, 2026 | $182,160 | (N) Detached A D U With (N) Attached Deck |
| B29304 | HVAC / heat pump | Issued | Iss. Apr 5, 2022 | $3,000 | Replace failed furnace with new furnace — Replace Mechanical Appliance |
| B28800 | Plumbing / water heater / sewer | Issued | Iss. Feb 21, 2022 | $1,800 | Replace failed tankless with new tankless WH. Run dedicated 3/4'' galvanized gas line from meter to 199k tankless in att… |
| 146097 | Solar / battery storage | Issued | Iss. Mar 5, 2015 | $6,700 |