1 De Silva Island Ct
Mill Valley 94941 · Strawberry · Unincorporated Marin · Coordinates: 37.88665, -122.51492
Executive Verdict · Public-Records Synthesis
Zoned RMP-1.5-BFC in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood due diligence; benchmark value $2,397,000 ($2,109,000–$2,685,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-1.5-BFC allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$149,040 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Apr 15, 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
- ! FEMA Special Flood Hazard Area (AE, about 7% 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)
- ! Delayed or open permit activity on this parcel
New garage / accessory structure (179041): Issued after 23 mo (4.3× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 3 slow or stalled nearby projects within ½ mile
Closest lead: Accessory dwelling unit at 25 Vista Del Sol (0.43 mi N, 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 (~$28,016/yr at $2,397,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,335/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:
- 12,240 sq ft (0.28 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 1 DE SILVA ISLAND CT
Zoning & Land Use
RMP-1.5-BFC — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-1.5-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-1.5-BFC (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-1.5-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 AE: 1% annual chance flood (Special Flood Hazard Area) (about 7% of the lot); Zone X: minimal flood hazard (about 93% 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: $2,109,000 – $2,685,000 · 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 garage / accessory structure (179041) (Issued)On this parcel
Issued after 23 mo (4.3× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
- Addition (adds square footage) (179040) (Issued)On this parcel
Issued after 23 mo (4.4× the 160d median) — slower than 90% of addition (adds square footage) permits in Unincorporated Marin (median 160d, 90th pct 440d, n=316).
- General repair (92011) (Applied)On this parcel
Pending in review for 2.7 yr (11.7× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
- Accessory dwelling unit at 25 Vista Del Sol (Applied)0.43 mi N
In "Applied" for 2.1 yr (since Oct 11, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
Entity-resolved builders & contractors in ½ mile: Utopia Design And Construction (2 on parcel, 2 in ½ mi · Addition (adds square footage)); North Coast Remodeling (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Icon General Contractors (4 in ½ mi · Commercial tenant improvement); Owner Builder (4 in ½ mi · Remodel / interior alteration); Owner (4 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 179041 | New garage / accessory structure | Issued | Iss. Apr 15, 2025 | $330,000 | Extend Deck With Ret Wall; Outdoor Kitchen & Trellis |
| 179040 | Addition (adds square footage) | Issued | Iss. Apr 15, 2025 | $207,000 | Remodel & Addition |
| 92011 | General repair | Applied | App. Mar 19, 2024 | $75,000 | Retaining Wall To Extend Driveway Turnabout |
| 146575 | Remodel / interior alteration | Issued | Iss. Apr 8, 2015 | $35,000 | Remodel Game Room To 2 Bedrooms - Express ***Expired 4/8/17 |