57 Dolphin Isle
Novato 94949 · Bel Marin Keys · Unincorporated Marin · Coordinates: 38.07646, -122.51530
Executive Verdict · Public-Records Synthesis
Zoned RSP-1.6-BFC in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood due diligence; benchmark value $1,568,000 ($1,380,000–$1,756,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RSP-1.6-BFC allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$218,570 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Mar 31, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Watchouts & Due Diligence
- ! FEMA Special Flood Hazard Area (AE, about 42% 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)
- ! 3 slow or stalled nearby projects within ½ mile
Closest lead: Demolition at 18 Dolphin Isle (0.1 mi 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 (~$18,482/yr at $1,568,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,540/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:
- 9,714 sq ft (0.22 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 57 DOLPHIN ISLE
Zoning & Land Use
RSP-1.6-BFC — Residential Single Family Planned (Unincorporated Marin)
Undesignated — Undesignated (Novato)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-1.6-BFC (single-family residential): state law allows ADUs where homes are allowed. The parcel point also falls in Undesignated.
- SB 9: two homes on the lotPossible, with conditions
Zoned RSP-1.6-BFC, a single-family residential zone. The parcel point also falls in Undesignated. FEMA Special Flood Hazard Area (Zone AE) covers about 42% 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-1.6-BFC, a single-family residential zone. The parcel point also falls in Undesignated. The lot is 9,714 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 42% 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 42% of the lot); Zone X: 0.2% annual chance flood hazard (shaded X) (about 58% of the lot) · FIRM panel 06041C0284E, 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: $1,380,000 – $1,756,000 · Status: Off market
HUD Small Area FMR (ZIP 94949) · FY 2026
Studio $2,360 · 1BR $2,830 · 2BR $3,430 · 3BR $4,380 · 4BR $4,540
Developments Deserving Closer Investigation & Active Area Builders
- Demolition at 18 Dolphin Isle (Issued)0.1 mi NW
Active in "Issued" for 11.6 yr (first record Mar 25, 2015) with no new permit activity recorded in 11.6 yr.
- Demolition at 1051 Bel Marin Keys Blvd (Issued)0.4 mi N
Active in "Issued" for 8.5 yr (first record May 21, 2018) with no new permit activity recorded in 8.4 yr.
- Accessory dwelling unit at 1108 Bel Marin Keys Blvd (aka 1110) (Issued)0.43 mi NE
Active in "Issued" for 4.6 yr (first record Mar 23, 2022) with no new permit activity recorded in 4.4 yr.
Entity-resolved builders & contractors in ½ mile: Millstreet Builders (1 on parcel, 1 in ½ mi · Addition (adds square footage)); Modern Green Constructions (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Peter Levi Plumbing (1 on parcel, 1 in ½ mi · HVAC / heat pump); Roof And Gutter Busters (1 on parcel, 1 in ½ mi · Roof replacement); Ernest Ongaro And Sons (1 on parcel, 1 in ½ mi · Electrical / panel).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B41814 | HVAC / heat pump | Issued | Iss. Mar 31, 2025 | $23,000 | Remove & replace furnace in closet like for like. Furnish & install AC in yard — Mechanical Appliance, Replace Mechanica… |
| 175763 | Addition (adds square footage) | Issued | Iss. Jan 17, 2024 | $350,000 | Addition; Remodel; Decks |
| B36650 | Electrical / panel | Issued | Iss. Jan 10, 2024 | $2,000 | Adding dedicated 60 amp circuit from main panel for a Nema 14-50 outlet in garage. Panel rejuvenation/tune-up by replaci… |
| B33096 | Roof replacement | Issued | Iss. Mar 22, 2023 | $22,000 | Roof installation base on 26 sq. Class A. Remove old roof shingle, install #30 underlayment. Install roof vent. — ReRoof… |
| 172875 | Remodel / interior alteration |