323 Ross Dr
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87717, -122.52957
Parcel & Assessor
- Lot size:
- 8,756 sq ft (0.20 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 323 ROSS DR; 325 ROSS DR
Zoning & Land Use
R1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotPossible, with conditions
Zoned R1, a single-family residential zone. FEMA regulatory floodway covers about 98% of the lot: SB 9 requires a no-rise certification.
- SB 9: split into two lotsPossible, with conditions
Zoned R1, a single-family residential zone. The lot is 8,756 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. FEMA regulatory floodway covers about 98% of the lot: SB 9 requires a no-rise certification.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate Fire Hazard Severity Zone (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone AE: 1% annual chance flood (Special Flood Hazard Area) (about 2% of the lot); Zone AE: regulatory floodway (Special Flood Hazard Area) (about 98% 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)
Range: $2,077,000 – $2,643,000 · 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 334 Dolan Ave (Issued)0.27 mi N
Active in "Issued" for 8.1 yr (first record Sep 5, 2018) with no new permit activity recorded in 7.9 yr. High-impact scale (1 housing unit, $759,000 declared valuation across 1 permit).
- New commercial building at 201 Flamingo Rd (aka 205) (Issued)0.32 mi NE
Active in "Issued" for 11.7 yr (first record Feb 17, 2015) with no new permit activity recorded in 11.2 yr. High-impact scale ($3,938,400 declared valuation across 3 permits).
- Accessory dwelling unit at 403 Marin Ave (adu 403a) (Issued)0.34 mi W
Active in "Issued" for 2.9 yr (first record Dec 21, 2023) with no new permit activity recorded in 18 mo. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
- New home at 407 Spruce St (Issued)0.37 mi W
Active in "Issued" for 7.6 yr (first record Mar 14, 2019) with no new permit activity recorded in 7.4 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
Permit & Project History on This Parcel (3 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B42965 | Roof replacement | Issued | Iss. Jul 2, 2025 | $17,825 | 1. REMOVE EXISTING ROOF DOWN TO THE BASE SHEATHING, INSPECT FOR DRY ROT. 2. INSTALLNEW SYNTHETIC ROOIFNG UNDERLAYMENT. 3… |
| 175145 | Accessory dwelling unit (new or conversion) | Issued | Iss. Oct 6, 2023 | $3,500 | Legalize & Remodel A D U - B W O P |
| 150482 | Roof replacement | Issued | Iss. Jan 25, 2016 | $7,500 | Tear-Off & Re-Roof***Extended 1/25/19 |
State HCD Housing Element APR records on this parcel: 2 entries (report years 2023, 2024).