661 Ridgewood Ave
Mill Valley 94941 · Homestead · Unincorporated Marin · Coordinates: 37.90100, -122.55265
Executive Verdict · Public-Records Synthesis
Zoned R1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $2,289,000 ($2,014,000–$2,564,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 6,447 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$150,000 contributory est.)
Public building records show issued construction/renovation work on this parcel (2 total permits, latest Feb 10, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Homestead
22 substantial renovation & housing permits over 24 months (20.7 per 1,000 parcels vs. 16.4 citywide baseline) (#2 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Homestead)
Watchouts & Due Diligence
- ! Mapped flood awareness zone (Zone X: minimal flood hazard)
all of the lot of the parcel intersects Zone X: minimal flood hazard. Outside mandatory federal SFHA insurance rules, but check local drainage and finished-floor requirements.
Source: FEMA National Flood Hazard Layer (parcel polygon)
- ! CAL FIRE High Fire Hazard Severity Zone (State Responsibility Area) (about 98% 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 Apr 1, 2024)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home (0.23 mi E, entitled). 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 (~$26,774/yr at $2,289,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,231/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:
- 6,447 sq ft (0.15 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 661 RIDGEWOOD AVE
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 lotLikely eligible
Zoned R1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1, a single-family residential zone. The lot is 6,447 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- High Fire Hazard Severity Zone (State Responsibility Area) (about 98% of the lot, map Apr 1, 2024); High Fire Hazard Severity Zone (Local Responsibility Area) (about 2% 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: $2,014,000 – $2,564,000 · 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 (Entitled)0.23 mi E
In "Entitled" for 6.3 yr (since Aug 11, 2020), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). High-impact scale (1 housing unit, 1 deed-restricted affordable across 0 permits).
- MFR/Office Overlay (Entitled)0.47 mi NE
In "Entitled" for 13 mo (since Oct 13, 2025), exceeding the 292d median and 313d 90th percentile for new multifamily / condos / mixed-use permits in Unincorporated Marin (n=21). High-impact scale (5 housing units across 0 permits).
- New home at 2 Hart Ln (Issued)0.22 mi E
Active in "Issued" for 6.9 yr (first record Dec 18, 2019) with no new permit activity recorded in 5.9 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- New home at 420 Laverne Ave (Issued)0.3 mi SE
Active in "Issued" for 8.6 yr (first record Apr 23, 2018) with no new permit activity recorded in 3.8 yr. High-impact scale (1 housing unit, $1,100,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Yonts Construction (1 on parcel, 1 in ½ mi · Remodel / interior alteration); De Mello Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Owner Builder (28 in ½ mi · Remodel / interior alteration); Owner (13 in ½ mi · Remodel / interior alteration); Buck Oneill Builders (3 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (2 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181074 | Remodel / interior alteration | Issued | Iss. Feb 10, 2026 | $555,000 | Structural Remodel; Deck & Railing |
| B24813 | Roof replacement | Issued | Iss. Feb 5, 2021 | $10,350 | TEAR OFF EXISTING BUILT-UP ROOF INSTALL NEW BUILT-UP ROOF CLASS A — ReRoofing |