20 Heron Ct
San Quentin 94964 · San Quentin · Unincorporated Marin · Coordinates: 37.94137, -122.48284
Executive Verdict · Public-Records Synthesis
Zoned RMP-6-BFC in Unincorporated Marin with likely ministerial ADU eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $1,385,000 ($1,177,000–$1,593,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-6-BFC allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ 3 documented municipal building permits on file
On-parcel permit history is indexed through Aug 13, 2025, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
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)
- ! Delayed or open permit activity on this parcel
Other (176032): Issued after 2 mo — above the 75th percentile for other permits in Unincorporated Marin (median 0d, 75th pct 1d, n=1,560).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 1 slow or stalled nearby project within ½ mile
Closest lead: New home at 22 Mckenzie St (290 ft NW, issued). 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 (~$16,378/yr at $1,385,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,365/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:
- 1,133 sq ft (0.03 ac)
- Assessor use:
- Single Family Attached
- Addresses on lot:
- 20 HERON CT
Zoning & Land Use
RMP-6-BFC — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-6-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-6-BFC (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-6-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 06041C0478E, 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: $1,177,000 – $1,593,000 · Status: Off market
HUD Small Area FMR (ZIP 94964) · FY 2026
Studio $2,530 · 1BR $3,040 · 2BR $3,680 · 3BR $4,700 · 4BR $4,870
Nearby Activity (½ mile radius, since November 2024)
0 active or recent development projects and 12 total building permits recorded within ½ mile.
- Additions & renovations2 permits
- Building systems8 permits
Developments Deserving Closer Investigation & Active Area Builders
- New home at 22 Mckenzie St (Issued)290 ft NW
Active in "Issued" for 3.9 yr (first record Dec 27, 2022) with no new permit activity recorded in 2.8 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
- Other (176032) (Issued)On this parcel
Issued after 2 mo — above the 75th percentile for other permits in Unincorporated Marin (median 0d, 75th pct 1d, n=1,560).
Entity-resolved builders & contractors in ½ mile: Pagan Construction (1 on parcel, 1 in ½ mi · Other); Larkspur Building (1 on parcel, 1 in ½ mi · Windows / doors / siding); Ernest Ongaro And Sons (1 on parcel, 1 in ½ mi · HVAC / heat pump); James Flanagan Builder (2 in ½ mi · New garage / accessory structure); Rodd Renovations (1 in ½ mi · New single-family home).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B43463 | Windows / doors / siding | Issued | Iss. Aug 13, 2025 | $14,000 | Replace five windows and one door in existing openings. Units are same size as oringinals and meet WUI and energy requir… |
| 176032 | Other | Issued | Iss. Feb 21, 2024 | $35,000 | Replace Deck |
| B29576 | HVAC / heat pump | Issued | Iss. Apr 29, 2022 | $7,400 | Replace failed furnace and ducting with new furnace and ducting AFUE 80%, R-6 — Replace Ductwork, Replace Mechanical App… |