517 Montford Ave
Mill Valley 94941 · Homestead · Unincorporated Marin · Coordinates: 37.89889, -122.55121
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 $2,248,000 ($1,978,000–$2,518,000).
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 11,064 sq ft lot. Local precedent is active with 3 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$17,094 contributory est.)
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Nov 9, 2021).
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) (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 Apr 1, 2024)
- ! Delayed or open permit activity on this parcel
Solar / battery storage (165136): Issued after 2 mo — slower than 90% of solar / battery storage permits in Unincorporated Marin (median 0d, 90th pct 2d, n=2,977).
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 (0.19 mi NE, 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)
Parcel & Assessor
- Lot size:
- 11,064 sq ft (0.25 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 517 MONTFORD 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 11,064 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) (all of the lot, map Apr 1, 2024)
- 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: $1,978,000 – $2,518,000 · 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)0.19 mi NE
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).
- New home (Entitled)0.44 mi E
In "Entitled" for 6.4 yr (since Jun 23, 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).
- Solar / battery storage (165136) (Issued)On this parcel
Issued after 2 mo — slower than 90% of solar / battery storage permits in Unincorporated Marin (median 0d, 90th pct 2d, n=2,977).
- New home at 420 Laverne Ave (Issued)0.14 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: Sunworks United (3 on parcel, 3 in ½ mi · Electrical / panel); Lawrence Roofing And Associates (1 on parcel, 1 in ½ mi · Roof replacement); Simpson Sheet Metal (1 on parcel, 1 in ½ mi · HVAC / heat pump); Owner Builder (37 in ½ mi · Remodel / interior alteration); Owner (18 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B27695 | Electrical / panel | Issued | Iss. Nov 9, 2021 | $2,500 | MPU-200A — Service Upgrade |
| B27015 | Solar / battery storage | Issued | Iss. Sep 15, 2021 | $13,300 | Install energy storage unit(battery) 13.5 KWh to (E) PV system |
| 165136 | Solar / battery storage | Issued | Iss. Jul 16, 2020 | $31,270 | Photovoltaic 4.55kw & 2 Energy Storage Systems 10/1/20 (60.1) Ess Removed From Scope Of Work |
| 165006 | General repair | Issued | Iss. Jun 26, 2020 | $15,000 | Termite Repairs To Front Parking Deck Termite Report #182587. T.D. 6/4/20 |
| B22581 | Roof replacement | Issued | Iss. May 15, 2020 |