12 Heron Dr
Mill Valley 94941 · Strawberry · Unincorporated Marin · Coordinates: 37.88108, -122.49736
Executive Verdict · Public-Records Synthesis
Zoned RMP-4-BFC in Unincorporated Marin with likely ministerial ADU eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,209,000 ($1,944,000–$2,474,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-4-BFC allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$8,191 contributory est.)
Public building records show issued construction/renovation work on this parcel (7 total permits, latest Aug 25, 2025).
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: New home (0.21 mi W, entitled). 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 (~$25,854/yr at $2,209,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,154/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:
- 9,235 sq ft (0.21 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 12 HERON DR
Zoning & Land Use
RMP-4-BFC — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-4-BFC (multifamily residential): state law allows ADUs where homes are allowed. On a multifamily lot the state allowance is different: ADUs in non-living space of the building, plus up to eight detached ADUs.
- SB 9: two homes on the lotUnlikely
Zoned RMP-4-BFC (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-4-BFC (multifamily residential), not a single-family residential zone.
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 06041C0488E, 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: $1,944,000 – $2,474,000 · 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
- New home (Entitled)0.21 mi W
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 171 Great Cir Dr (Applied)0.24 mi W
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).
- Demolition at 7 Heron Dr (Issued)290 ft NW
Active in "Issued" for 9.6 yr (first record Apr 13, 2017) with no new permit activity recorded in 9.5 yr.
- Accessory dwelling unit at 23 Weatherly Dr (Issued)0.12 mi NW
Active in "Issued" for 5.7 yr (first record Mar 9, 2021) with no new permit activity recorded in 5 yr.
Entity-resolved builders & contractors in ½ mile: Peter Levi Plumbing (2 on parcel, 2 in ½ mi · HVAC / heat pump); Jemico (1 on parcel, 1 in ½ mi · Windows / doors / siding); Federighi Robert General Contractor (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Divine Electric (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Hulbert Heating And Air Conditioning (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (7 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B43599 | HVAC / heat pump | Issued | Iss. Aug 25, 2025 | $12,489 | Install a 9k BTU Mitsubishi ducted heat pump — Replace Mechanical Appliance |
| B35567 | Roof replacement | Issued | Iss. Sep 28, 2023 | $7,000 | Reroofing — ReRoofing |
| B27941 | Plumbing / water heater / sewer | Issued | Iss. Dec 1, 2021 | $15,500 | REMOVE EXISTING BOILER AND INDIRECT WATERHEATER INSTALL NAVIEN NCB 240 COMBINATION BOILER WATERHEATER WITH PRIMARY LOOP … |
| B25827 | Windows / doors / siding | Issued | Iss. May 24, 2021 | $24,546 | Replacing 8 retrofit windows. — Non-structural Door/Window Replacement |
| 164101 | Plumbing / water heater / sewer | Issued |