742 Alta Vista Rd
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87677, -122.54212
Executive Verdict · Public-Records Synthesis
Zoned R1-B1 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 $2,141,000 ($1,884,000–$2,398,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 7,013 sq ft lot. Local precedent is active with 4 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$47,238 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Jun 23, 2022).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Tamalpais
50 substantial renovation & housing permits over 24 months (20.5 per 1,000 parcels vs. 16.4 citywide baseline) (#3 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Tamalpais)
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: Accessory dwelling unit at 875 Marin Dr (0.2 mi SW, 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)
- ! Year 1 Prop 13 tax reset (~$25,072/yr at $2,141,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,089/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:
- 7,013 sq ft (0.16 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 742 ALTA VISTA RD
Zoning & Land Use
R1-B1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B1, a single-family residential zone. The lot is 7,013 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: $1,884,000 – $2,398,000 · 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
- Accessory dwelling unit at 875 Marin Dr (Applied)0.2 mi SW
In "Applied" for 2.6 yr (since Apr 11, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). Record changed to "updated" in snapshot Nov 4, 2026.
- New home at 746 Alta Vista Rd (Issued)150 ft S
Active in "Issued" for 3.3 yr (first record Jul 19, 2023) with no new permit activity recorded in 2.3 yr. High-impact scale (1 housing unit, $1,183,700 declared valuation across 2 permits).
- New home at 760 Bay Rd (Issued)270 ft NE
Active in "Issued" for 9.4 yr (first record Jun 12, 2017) with no new permit activity recorded in 8.4 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- New home at 808 Spring Dr (Issued)450 ft SW
Active in "Issued" for 4.9 yr (first record Dec 13, 2021) with no new permit activity recorded in 4.7 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Owner (1 on parcel, 27 in ½ mi · Remodel / interior alteration); Maap (1 on parcel, 1 in ½ mi · Windows / doors / siding); Raully Jones Construction (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Mc Leran (1 on parcel, 1 in ½ mi · Roof replacement); Owner Builder (61 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 171751 | Remodel / interior alteration | Issued | Iss. Jun 23, 2022 | $33,438 | Bath Remodel - Express |
| B29701 | Windows / doors / siding | Issued | Iss. May 13, 2022 | $46,136 | Replace 26 Retrofit windows & 1 Sliding Patio Door & 2 Outswing French Doors New Construction - All In-Kind - WUI Glass.… |
| 159387 | Remodel / interior alteration | Issued | Iss. Aug 22, 2018 | $85,000 | Rmdl Mstr Bd/Bth,. Skyligh & Windw To Slider T.D. 5/17/18 |
| 150027 | Roof replacement | Issued | Iss. Dec 3, 2015 | $16,300 | Re-Roof -E Permit |