20 Hillcrest Rd
Tiburon 94920 · Unincorporated Tiburon · Unincorporated Marin · Coordinates: 37.90477, -122.48079
Executive Verdict · Public-Records Synthesis
Zoned R1-B2 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $3,197,000 ($2,813,000–$3,581,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B2 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 13,809 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$14,400 contributory est.)
Public building records show issued construction/renovation work on this parcel (3 total permits, latest Aug 26, 2021).
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)
- ! CAL FIRE Moderate Fire Hazard Severity Zone (State Responsibility Area) (all of the lot of lot)
Located in a mapped Fire Hazard Severity Zone. Expect Chapter 7A ignition-resistant building standards, defensible-space inspections, and stricter property insurance underwriting.
Source: CAL FIRE FHSZ (map Apr 1, 2024)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home (0.17 mi S, 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 (~$37,216/yr at $3,197,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$3,101/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:
- 13,809 sq ft (0.32 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 20 HILLCREST RD
Zoning & Land Use
R1-B2 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B2, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B2, a single-family residential zone. The lot is 13,809 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate Fire Hazard Severity Zone (State Responsibility Area) (all of the lot, map Apr 1, 2024)
- 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: $2,813,000 – $3,581,000 · Status: Off market
HUD Small Area FMR (ZIP 94920) · FY 2026
Studio $2,820 · 1BR $3,380 · 2BR $4,100 · 3BR $5,230 · 4BR $5,420
Developments Deserving Closer Investigation & Active Area Builders
- New home (Issued)0.17 mi S
Active in "Issued" for 3.8 yr (first record Feb 9, 2023) with no new permit activity recorded in 3.8 yr.
- New home (Issued)0.35 mi SE
Active in "Issued" for 2.2 yr (first record Sep 11, 2024) with no new permit activity recorded in 2.2 yr.
- New home at 4134 Paradise Dr (aka 4130) (Issued)0.37 mi E
Active in "Issued" for 4.4 yr (first record Jun 2, 2022) with no new permit activity recorded in 4.2 yr.
- New home (Issued)0.39 mi SW
Active in "Issued" for 17 mo (first record Jun 18, 2025) with no new permit activity recorded in 17 mo.
Entity-resolved builders & contractors in ½ mile: Copp Roofing And Construction (1 on parcel, 1 in ½ mi · Roof replacement); Sunrun Installation Service (1 on parcel, 1 in ½ mi · Solar / battery storage); Sunrun Installation Services (1 on parcel, 1 in ½ mi · Electrical / panel); Owner (5 in ½ mi · New garage / accessory structure); Owner Builder (4 in ½ mi · Addition (adds square footage)).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B26790 | Roof replacement | Issued | Iss. Aug 26, 2021 | $55,585 | FULL TILE REPLACEMENT (concrete W tile) — ReRoofing |
| 169062 | Solar / battery storage | Issued | Iss. Aug 10, 2021 | $45,000 | 11.1kw Rooftop Photovoltaic And Energy Storage System |
| B26535 | Electrical / panel | Issued | Iss. Aug 6, 2021 | $2,000 | Replace existing main panel and main breaker with new 100A main panel and new 100A main breaker — Service Upgrade |