326 Robin Rd
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87769, -122.52827
Executive Verdict · Public-Records Synthesis
Zoned R1-B1 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood / CAL FIRE moderate fire hazard severity zone (local responsibility area) due diligence; benchmark value $2,135,000 ($1,879,000–$2,391,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone R1-B1 allows residential use qualifying for ministerial ADU review under state law (7 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$52,804 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Jul 17, 2023).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Tamalpais
50 substantial renovation & housing permits over 24 months (20.5 per 1,000 parcels vs. 16.4 citywide baseline) (#3 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Tamalpais)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 96% of the lot of lot)
Zone AE: regulatory floodway (Special Flood Hazard Area) overlaps this parcel. Expect mandatory flood insurance for federally backed loans and floodplain elevation/mitigation rules for new units or SB 9 applications.
Source: FEMA National Flood Hazard Layer (parcel polygon)
- ! CAL FIRE Moderate Fire Hazard Severity Zone (Local Responsibility Area) (about 31% 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 Mar 24, 2025)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 334 Dolan Ave (0.24 mi N, issued). 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 (~$25,003/yr at $2,135,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,084/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:
- 6,534 sq ft (0.15 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 326 ROBIN RD
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 regulatory floodway covers about 96% of the lot: SB 9 requires a no-rise certification.
- SB 9: split into two lotsPossible, with conditions
Zoned R1-B1, a single-family residential zone. The lot is 6,534 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 96% 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) (about 31% of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone AE: regulatory floodway (Special Flood Hazard Area) (about 96% of the lot); Zone AH: 1% annual chance flood (Special Flood Hazard Area) (about 4% 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: $1,879,000 – $2,391,000 · 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)0.24 mi N
Active in "Issued" for 8.2 yr (first record Sep 5, 2018) with no new permit activity recorded in 8 yr. High-impact scale (1 housing unit, $759,000 declared valuation across 1 permit).
- New home at 535 Tennessee Valley Rd (adu 531) (Issued)0.39 mi S
Active in "Issued" for 6 yr (first record Oct 29, 2020) with no new permit activity recorded in 4 yr. High-impact scale (1 housing unit, $800,000 declared valuation across 1 permit).
- Accessory dwelling unit at 403 Marin Ave (adu 403a) (Issued)0.41 mi W
Active in "Issued" for 2.9 yr (first record Dec 21, 2023) with no new permit activity recorded in 19 mo. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
- New home at 407 Spruce St (Issued)0.43 mi W
Active in "Issued" for 7.7 yr (first record Mar 14, 2019) with no new permit activity recorded in 7.5 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Owner Builder (1 on parcel, 69 in ½ mi · Remodel / interior alteration); Marin Kitchen (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Sunpower (1 on parcel, 1 in ½ mi · Solar / battery storage); Marin County Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Owner (44 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 174525 | Remodel / interior alteration | Issued | Iss. Jul 17, 2023 | $30,000 | Non Structural Bathroom Remodel |
| B34072 | Solar / battery storage | Issued | Iss. May 25, 2023 | $16,800 | INSTALLATION OF ROOF-MOUNTED PV SYSTEM - 8.4 KW (21 MODULES) 100A LOAD CENTER |
| 156066 | Remodel / interior alteration | Issued | Iss. Jul 25, 2017 | $88,762 | Rmdl Kitchen & Master Bath; 200 A Service Upgrade; Repl Water Heater W/Tankless In Flood Zone - Must Go To L.D. |
| 147209 | Remodel / interior alteration | Issued | Iss. May 20, 2015 | $16,000 | Rmdl Ba, Reloc Water Heater And Change To Tankless |
| 144139 | Roof replacement | Issued |