688 Sequoia Valley Rd
Mill Valley 94941 · Muir Woods Park · Unincorporated Marin · Coordinates: 37.89768, -122.55881
Executive Verdict · Public-Records Synthesis
Zoned R1-B3 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 $2,417,000 ($2,127,000–$2,707,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B3 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 27,704 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$132,000 contributory est.)
Public building records show issued construction/renovation work on this parcel (7 total permits, latest Apr 22, 2024).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
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
Demolition at 688 Sequoia Valley Rd: In "Applied" for 3.2 yr (since Sep 6, 2023), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
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 (0.31 mi W, 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:
- 27,704 sq ft (0.64 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 688 SEQUOIA VALLEY RD
Zoning & Land Use
R1-B3 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B3 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B3, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B3, a single-family residential zone. The lot is 27,704 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: $2,127,000 – $2,707,000 · 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
- Demolition at 688 Sequoia Valley Rd (Applied)On this parcel
In "Applied" for 3.2 yr (since Sep 6, 2023), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
- New home at 65 Ridge Ave (Applied)0.31 mi W
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).
- Demolition (91476) (Applied)On this parcel
Pending in review for 3.2 yr (21.1× the 55d median) — slower than 90% of demolition permits in Unincorporated Marin (median 55d, 90th pct 261d, n=130).
- New home at 420 Laverne Ave (Issued)0.5 mi E
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: Reyff Electric (2 on parcel, 2 in ½ mi · Electrical / panel); Tanoak Construction (1 on parcel, 1 in ½ mi · Addition (adds square footage)); Sustainable Living Builders (1 on parcel, 1 in ½ mi · Roof replacement); Apollo Building And Roofing Group (1 on parcel, 1 in ½ mi · Roof replacement); John Owens Services (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer).
Permit & Project History on This Parcel (7 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B37750 | Roof replacement | Issued | Iss. Apr 22, 2024 | $9,000 | PARTIAL ROOF REPAIR OF 3/6SQ TEAR OFF INSTLL SHINGLES & 3/6SQ TEAR OFF INSTALL MODIFIED BITUMEN — ReRoofing |
| B37218 | Electrical / panel | Issued | Iss. Mar 4, 2024 | $5,280 | Remove a 100 Amp Electrical Panel and Replace with a 200 Amp Electrical Panel. — Service Upgrade |
| B37185 | Electrical / panel | Issued | Iss. Feb 29, 2024 | $3,660 | Remove an old Electric Load Center and Replace with a new 100 Amp Load Center. — Service Upgrade |
| 175530 | Addition (adds square footage) | Issued | Iss. Dec 1, 2023 |