506 Shasta Way
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.88178, -122.53907
Executive Verdict · Public-Records Synthesis
Zoned RA-B2 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $2,187,000 ($1,925,000–$2,449,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RA-B2 allows residential use qualifying for ministerial ADU review under state law (4 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$19,080 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Feb 15, 2024).
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 Moderate 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: New home at 560 Alta Way (0.27 mi N, 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 (~$25,601/yr at $2,187,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,133/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:
- 10,977 sq ft (0.25 ac)
- Assessor use:
- Multiple-Resid. - Improved
- Addresses on lot:
- 506 SHASTA WAY; 508 SHASTA WAY
Zoning & Land Use
RA-B2 — Residential Agriculture (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RA-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotCan't tell
Zoned RA-B2 (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
- SB 9: split into two lotsCan't tell
Zoned RA-B2 (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate 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: $1,925,000 – $2,449,000 · 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
Nearby Activity (½ mile radius, since November 2024)
23 active or recent development projects (22 housing units across completed, permitted, and pipeline stages) and 549 total building permits recorded within ½ mile.
- New construction6 permits (4 units)
- Adds housing (ADU)18 permits (18 units)
- Demolition2 permits
- Additions & renovations29 permits
- Building systems388 permits
- Repairs18 permits
- Other88 permits
Developments Deserving Closer Investigation & Active Area Builders
- New home at 560 Alta Way (Applied)0.27 mi N
In "Applied" for 3.3 yr (since Aug 10, 2023), 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, $975,000 declared valuation across 1 permit).
- New home at 731 Bay Rd (Issued)0.23 mi S
Active in "Issued" for 18 mo (first record May 12, 2025) with no new permit activity recorded in 15 mo. High-impact scale (1 housing unit, $955,000 declared valuation across 1 permit).
- Accessory dwelling unit at 403 Marin Ave (adu 403a) (Issued)0.32 mi SE
Active in "Issued" for 2.9 yr (first record Dec 21, 2023) with no new permit activity recorded in 19 mo. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
- New home at 469 W Live Oak Dr (aka 461) (Issued)0.38 mi S
Active in "Issued" for 6.1 yr (first record Oct 22, 2020) with no new permit activity recorded in 22 mo. High-impact scale (1 housing unit, $980,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Sunrun Installation Service (2 on parcel, 2 in ½ mi · Solar / battery storage); Gutierrez Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Pedro Femenia And Sons (1 on parcel, 1 in ½ mi · HVAC / heat pump); Owner Builder (95 in ½ mi · Remodel / interior alteration); Owner (48 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B37027 | HVAC / heat pump | Issued | Iss. Feb 15, 2024 | $5,940 | Replace furnace with like furnace. Natural gas 45k BTU . Tying into existing gas and flue lines. — Replace Plumbing Fixt… |
| 168364 | Solar / battery storage | Issued | Iss. Jun 4, 2021 | $31,000 | 4.68 Kw Rooftop Photovoltaic & Energy Storage System |
| 168363 | Solar / battery storage | Issued | Iss. Jun 4, 2021 | $22,000 | 3.60 Kw Rooftop Photovoltaic & Energy Storage System |
| B19655 | Roof replacement | Issued | Iss. Aug 26, 2019 | $15,000 | Re-roof Remove existing shingle layers and install class A composition shingles — ReRoofing |