6 Topside Way
Mill Valley 94941 · Strawberry · Unincorporated Marin · Coordinates: 37.88247, -122.50235
Executive Verdict · Public-Records Synthesis
Zoned RSP-5 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,301,000 ($2,025,000–$2,577,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RSP-5 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 14,113 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$28,490 contributory est.)
Public building records show issued construction/renovation work on this parcel (3 total permits, latest May 30, 2023).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Strawberry
43 substantial renovation & housing permits over 24 months (28.4 per 1,000 parcels vs. 16.4 citywide baseline) (#1 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Strawberry)
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: Demolition at 171 Great Cir Dr (250 ft E, 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 (~$26,912/yr at $2,301,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,243/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:
- 14,113 sq ft (0.32 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 6 TOPSIDE WAY
Zoning & Land Use
RSP-5 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-5 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-5, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-5, a single-family residential zone. The lot is 14,113 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
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0469F, 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: $2,025,000 – $2,577,000 · 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 171 Great Cir Dr (Applied)250 ft E
In "Applied" for 15 mo (since Aug 14, 2025), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
- New home (Entitled)410 ft SE
In "Entitled" for 5.1 yr (since Sep 30, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 604 Seminary Dr (Issued)520 ft NW
Active in "Issued" for 7.3 yr (first record Jul 17, 2019) with no new permit activity recorded in 7.3 yr.
- New home at 50 Great Cir Dr (Issued)0.16 mi SE
Active in "Issued" for 21 mo (first record Feb 18, 2025) with no new permit activity recorded in 17 mo.
Entity-resolved builders & contractors in ½ mile: Flint Construction (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Eclipse Energy And Construction (1 on parcel, 1 in ½ mi · Solar / battery storage); Arb (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Lek Enterprises (35 in ½ mi · Remodel / interior alteration); Owner Builder (21 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B34089 | Solar / battery storage | Issued | Iss. May 30, 2023 | $14,200 | Install 6.48kW of roof mount solar. main panel upgrade 200A. |
| B11076 | Plumbing / water heater / sewer | Issued | Iss. Sep 26, 2016 | $2,000 | Install gas line for PG&E meter relocation — New Plumbing Fixture(s) |
| 151626 | Remodel / interior alteration | Issued | Iss. Apr 18, 2016 | $65,000 | Struct Kit Rmdl T.D. 3/31/16 |