251 A Marin Ave
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87628, -122.52796
Parcel & Assessor
- Lot size:
- 5,576 sq ft (0.13 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 251A MARIN AVE; 251 MARIN 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 lotPossible, with conditions
Zoned R1-B1, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 23% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
- SB 9: split into two lotsPossible, with conditions
Zoned R1-B1, a single-family residential zone. The lot is 5,576 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. FEMA Special Flood Hazard Area (Zone AE) covers about 23% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- High Fire Hazard Severity Zone (State Responsibility Area) (about 99% of the lot, map Apr 1, 2024)
- FEMA National Flood Hazard Layer
- Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 23% of the lot); Zone X: 0.2% annual chance flood hazard (shaded X) (about 69% of the lot); Zone X: minimal flood hazard (about 7% of the lot) · FIRM panel 06041C0469F, effective March 16, 2016
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
HUD Small Area FMR (ZIP 94941) · FY 2026
Studio $2,730 · 1BR $3,270 · 2BR $3,960 · 3BR $5,060 · 4BR $5,240
Permit & Project History on This Parcel (5 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181954 | Accessory dwelling unit (new or conversion) | Issued | Iss. Jun 29, 2026 | $260,000 | New Two-Story Attached A D U; Deck |
| B44887 | Roof replacement | Issued | Iss. Nov 25, 2025 | $22,000 | Tear off existing roof and install new GAF reflector series shingles — ReRoofing; With Electronic Inspection |
| B41143 | EV charger | Issued | Iss. Feb 6, 2025 | $1,300 | Install Tee taps after main disconnect for a 4/8 subpanel to feed a 60A 240v Circuit for hardwired EV charger at 48a loa… |
| 169005 | Solar / battery storage | Issued | Iss. Aug 5, 2021 |