3 Ridge Ave
Mill Valley 94941 · Muir Woods Park · Unincorporated Marin · Coordinates: 37.90076, -122.56740
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 $2,285,000 ($2,011,000–$2,559,000).
Upsides & Opportunities
- ✓ 10 documented municipal building permits on file
On-parcel permit history is indexed through Nov 19, 2025, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
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 83% 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
Remodel / interior alteration (93289): Pending in review for 17 mo (6.1× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 2 slow or stalled nearby projects within ½ mile
Closest lead: New home at 65 Ridge Ave (0.28 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:
- 29,926 sq ft (0.69 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 3 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 29,926 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 83% of the lot); Zone X: minimal flood hazard (about 17% 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: $2,011,000 – $2,559,000 · 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)0.28 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).
- Remodel / interior alteration (93289) (Applied)On this parcel
Pending in review for 17 mo (6.1× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
- Other (159495) (Issued)On this parcel
Issued after 9 mo — slower than 90% of other permits in Unincorporated Marin (median 0d, 90th pct 71d, n=1,560).
- General repair (81185) (Applied)On this parcel
Pending in review for 8.9 yr (39.2× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
Entity-resolved builders & contractors in ½ mile: Owner Builder (3 on parcel, 29 in ½ mi · Remodel / interior alteration); Moore Home Services (1 on parcel, 1 in ½ mi · HVAC / heat pump); Ard Mhacha Construction (1 on parcel, 1 in ½ mi · Electrical / panel); Moore Services (1 on parcel, 1 in ½ mi · HVAC / heat pump); Moore Solar Heating Cooling (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (10 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B44836 | HVAC / heat pump | Issued | Iss. Nov 19, 2025 | $10,712 | FURNACE CHANGE OUT IN CLOSET 60K BTU, 80 AFUE — Replace Mechanical Appliance |
| 93289 | Remodel / interior alteration | Applied | App. Jun 23, 2025 | $800,000 | Remodel (E) Upper Level & Stairs And (N) Doors And Windows |
| 160243 | Electrical / panel | Issued | Iss. Dec 4, 2018 | $6,500 | Gas Line/Property Line Set. Moving Gas Line From House To Fence. Ref. Pn # 159494 |
| 159496 | New garage / accessory structure | Issued | Iss. Sep 5, 2018 | $20,000 | Pergola With Outdoor Kitchen T.D. 8/7/18 |
| 159495 | Other | Issued | Iss. Sep 5, 2018 |