543 Northern Ave
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.88128, -122.54213
Parcel & Assessor
- Lot size:
- 8,625 sq ft (0.20 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 543 NORTHERN AVE
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
- Moderate Fire Hazard Severity Zone (Local Responsibility Area) (about 99% of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0468F, 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: $2,106,000 – $2,680,000 · 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 731 Bay Rd (Issued)0.19 mi SE
Active in "Issued" for 18 mo (first record May 12, 2025) with no new permit activity recorded in 14 mo. High-impact scale (1 housing unit, $955,000 declared valuation across 1 permit).
- New home at 510 Browning Ct (Issued)0.25 mi NE
Active in "Issued" for 10.2 yr (first record Aug 15, 2016) with no new permit activity recorded in 9.9 yr. High-impact scale (1 housing unit, $900,000 declared valuation across 1 permit).
- New home at 760 Bay Rd (Issued)0.29 mi S
Active in "Issued" for 9.4 yr (first record Jun 12, 2017) with no new permit activity recorded in 8.4 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- New home at 560 Alta Way (Applied)0.3 mi N
Active in "Applied" for 3.2 yr (first record Aug 10, 2023) with no new permit activity recorded in 3.2 yr. High-impact scale (1 housing unit, $975,000 declared valuation across 1 permit).
Permit & Project History on This Parcel (5 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181933 | Accessory dwelling unit (new or conversion) | Issued | Iss. Jun 17, 2026 | $188,000 | Conversion Of (E) Garage To A D U, Addition To A D Ut.D. 2-20-26 3/25/26 - Refund Adu Fee Of $2500, Al |
| B44662 | Roof replacement | Issued | Iss. Nov 4, 2025 | $40,000 | Repair some dry rot and install tile over the balcony/roof — Siding Replacement, ReRoofing |
| 150461 | Solar / battery storage | Issued | Iss. Jan 21, 2016 | $8,000 | Roof Mount Photovoltaic 2.12 K W - Express |
| 142184 | HVAC / heat pump | Issued | Iss. Apr 9, 2014 | $6,562 |