331 Linda Way
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87702, -122.53004
Executive Verdict · Public-Records Synthesis
Zoned R1 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 $2,270,000 ($1,998,000–$2,542,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone R1 allows residential use qualifying for ministerial ADU review under state law (6 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$136,080 contributory est.)
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Feb 10, 2026).
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 78% 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) (all 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)
- ! Delayed or open permit activity on this parcel
Addition (adds square footage) (172496): Issued after 13 mo (2.5× the 160d median) — above the 75th percentile for addition (adds square footage) permits in Unincorporated Marin (median 160d, 75th pct 249d, n=316).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 5 slow or stalled nearby projects within ½ mile
Closest lead: New home at 334 Dolan Ave (0.28 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)
Parcel & Assessor
- Lot size:
- 8,930 sq ft (0.21 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 331 LINDA WAY
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 78% 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 8,930 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 78% 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: regulatory floodway (Special Flood Hazard Area) (about 78% of the lot); Zone X: minimal flood hazard (about 22% 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: $1,998,000 – $2,542,000 · 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)0.28 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).
- Accessory dwelling unit at 403 Marin Ave (adu 403a) (Issued)0.32 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 commercial building at 201 Flamingo Rd (aka 205) (Issued)0.35 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).
- New home at 407 Spruce St (Issued)0.35 mi NW
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: Hsc Services (1 on parcel, 3 in ½ mi · Remodel / interior alteration); Moore Services (2 on parcel, 2 in ½ mi · HVAC / heat pump); Able Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Athena Electrical Construction (1 on parcel, 1 in ½ mi · Electrical / panel); Owner Builder (70 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181079 | General repair | Issued | Iss. Feb 10, 2026 | $5,500 | Seismic Retrofit To Plan Set A Adding U R F P Brackets, Shear Plywood & L90s |
| 172496 | Addition (adds square footage) | Issued | Iss. Oct 6, 2022 | $216,000 | Addition & Remodel |
| B25967 | HVAC / heat pump | Issued | Iss. Jun 7, 2021 | $1,900 | INSTALLING 8 RUNS OF DUCTING — Replace Ductwork, Replace Mechanical Appliance |
| B25137 | HVAC / heat pump | Issued | Iss. Mar 14, 2021 | $12,000 | NEW 3 A/C UNIT ON RIGHT SIDE YARD (14 SEER ) AND C/O 45K BTU FAU IN GARAGE (96%) — Mechanical Appliance |
| B16878 | Roof replacement | Issued | Iss. Jan 21, 2019 |