12 Great Circle Dr
Mill Valley 94941 · Strawberry · Unincorporated Marin · Coordinates: 37.88239, -122.50318
Executive Verdict · Public-Records Synthesis
Zoned RSP-5 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood due diligence; benchmark value $2,447,000 ($2,153,000–$2,741,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RSP-5 allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$150,379 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Sep 23, 2024).
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
- ! FEMA Special Flood Hazard Area (AE, about 1% of the lot of lot)
Zone AE: 1% annual chance flood (Special Flood Hazard Area) overlaps this parcel. Expect mandatory flood insurance for federally backed loans and floodplain elevation/mitigation rules for new units or SB 9 applications.
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 (480 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 (~$28,591/yr at $2,447,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,383/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:
- 16,291 sq ft (0.37 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 12 GREAT CIRCLE DR
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 lotPossible, with conditions
Zoned RSP-5, a single-family residential zone. FEMA Special Flood Hazard Area (Zone AE) covers about 1% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
- SB 9: split into two lotsPossible, with conditions
Zoned RSP-5, a single-family residential zone. The lot is 16,291 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original. FEMA Special Flood Hazard Area (Zone AE) covers about 1% of the lot: the project must meet the National Flood Insurance Program floodplain standards, or the lot needs a map revision.
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 AE: 1% annual chance flood (Special Flood Hazard Area) (about 1% of the lot); Zone X: minimal flood hazard (about 99% 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: $2,153,000 – $2,741,000 · 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)480 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)0.12 mi E
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)410 ft N
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)0.18 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: Ongaro Ernest And Sons (2 on parcel, 2 in ½ mi · HVAC / heat pump); Vida Building (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Sonomarin Solar_inc (1 on parcel, 1 in ½ mi · Solar / battery storage); Lek Enterprises (35 in ½ mi · Remodel / interior alteration); Owner Builder (25 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B39566 | Solar / battery storage | Issued | Iss. Sep 23, 2024 | $29,900 | Photovoltaic - Residential Flush roof Mount, Grid Tied ESS Installation with (2) Tesla Powerwall 3 ESS Units 320A Main S… |
| 176330 | Remodel / interior alteration | Issued | Iss. Apr 4, 2024 | $600,000 | Convert (E) Basement To (N) Office; Remodel Main & Upper Levels; Windows & Doors |
| 150721 | Plumbing / water heater / sewer | Issued | Iss. Feb 10, 2016 | $1,800 | Repl Water Heater |
| 150627 | HVAC / heat pump | Issued | Iss. Feb 3, 2016 | $4,200 | Repl Furnace |