13 Ridge Ave
Mill Valley 94941 · Muir Woods Park · Unincorporated Marin · Coordinates: 37.90051, -122.56709
Executive Verdict · Public-Records Synthesis
Zoned R1-B3 in Unincorporated Marin and mapped CAL FIRE very high fire hazard severity zone (state responsibility area) due diligence; benchmark value $2,189,000 ($1,926,000–$2,452,000).
Upsides & Opportunities
- ✓ Documented permitted upgrades (+$59,400 contributory est.)
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Apr 27, 2017).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! Mapped flood awareness zone (Zone D: possible but undetermined flood hazard)
about 99% of the lot of the parcel intersects Zone D: possible but undetermined 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 Very 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
General repair (79029): Pending in review for 10 yr (43.9× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 4 slow or stalled nearby projects within ½ mile
Closest lead: New home at 65 Ridge Ave (0.26 mi SE, applied). 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:
- 9,670 sq ft (0.22 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 13 RIDGE AVE
Zoning & Land Use
R1-B3 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADUPossible, with conditions
Zoned R1-B3 (single-family residential): state law allows ADUs where homes are allowed. Very High Fire Hazard Severity Zone covers all of the lot: cities may limit ADUs here for fire safety and evacuation.
- SB 9: two homes on the lotPossible, with conditions
Zoned R1-B3, a single-family residential zone. Very High Fire Hazard Severity Zone (State responsibility area) covers all of the lot: SB 9 requires the project to meet the fire hazard mitigation standards.
- SB 9: split into two lotsPossible, with conditions
Zoned R1-B3, a single-family residential zone. The lot is 9,670 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. Very High Fire Hazard Severity Zone (State responsibility area) covers all of the lot: SB 9 requires the project to meet the fire hazard mitigation standards.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Very High Fire Hazard Severity Zone (State Responsibility Area) (all of the lot, map Apr 1, 2024)
- FEMA National Flood Hazard Layer
- Zone D: possible but undetermined flood hazard (about 99% of the lot); Zone X: minimal flood hazard (about 1% of the lot) · FIRM panel 06041C0465E, effective August 15, 2017
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,926,000 – $2,452,000 · 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 65 Ridge Ave (Applied)0.26 mi SE
In "Applied" for 4 yr (since Oct 27, 2022), 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, $3,000,000 declared valuation across 1 permit).
- General repair (79029) (Applied)On this parcel
Pending in review for 10 yr (43.9× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
- New home at 526 Panoramic Hwy (Issued)0.11 mi NW
Active in "Issued" for 4.6 yr (first record Apr 21, 2022) with no new permit activity recorded in 2.1 yr. High-impact scale (1 housing unit, $1,329,450 declared valuation across 2 permits).
- New home at 49 Ridge Ave (Applied)0.18 mi S
In "Applied" for 5.1 yr (since Oct 15, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
Entity-resolved builders & contractors in ½ mile: Owner Builder (2 on parcel, 29 in ½ mi · Remodel / interior alteration); Olin Frank Daunell Electrical Contr (1 on parcel, 1 in ½ mi · Electrical / panel); Ocallaghan Plumbing Dba Sonoma Marin Plumbing (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Drew Underground Construction (1 on parcel, 1 in ½ mi · Electrical / panel); Owner (9 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 155311 | Other | Issued | Iss. Apr 27, 2017 | $20,000 | Replace Deck T.D. 4/3/17 |
| 79029 | General repair | Applied | App. Nov 23, 2016 | $1,000 | Mods To 2 Joists In Ba - Express |
| 153796 | Electrical / panel | Issued | Iss. Nov 8, 2016 | $1,200 | Electric For Septic Sump Pump***Extended 11/8/19 |
| 152873 | Remodel / interior alteration | Issued | Iss. Aug 3, 2016 | $180,000 | Remod Kitch & Bath, Windows/Doors, Siding, Gas Fireplace Insert 7/11/16 |
| 152421 | Plumbing / water heater / sewer | Issued | Iss. Jun 20, 2016 | $15,500 |