31 Ellsworth Ln
Fairfax 94930 · Unincorporated Fairfax · Unincorporated Marin · Coordinates: 38.00482, -122.59208
Executive Verdict · Public-Records Synthesis
Zoned RSP-0.1 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 $1,269,000 ($1,117,000–$1,421,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RSP-0.1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 462,564 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 (5 total permits, latest Oct 16, 2023).
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)
- ! 5 slow or stalled nearby projects within ½ mile
Closest lead: New home at 40 De Burgh Dr (0.45 mi E, 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 (~$15,044/yr at $1,269,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,254/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:
- 462,564 sq ft (10.62 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 31 ELLSWORTH LN
Zoning & Land Use
RSP-0.1 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-0.1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-0.1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-0.1, a single-family residential zone. The lot is 462,564 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 06041C0289D, effective May 4, 2009
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,117,000 – $1,421,000 · Status: Off market
HUD Small Area FMR (ZIP 94930) · FY 2026
Studio $2,230 · 1BR $2,680 · 2BR $3,240 · 3BR $4,140 · 4BR $4,290
Developments Deserving Closer Investigation & Active Area Builders
- New home at 40 De Burgh Dr (Applied)0.45 mi E
In "Applied" for 9.3 yr (since Jul 31, 2017), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). High-impact scale (1 housing unit, $1,800,000 declared valuation across 3 permits).
- New home (Entitled)0.14 mi N
In "Entitled" for 5.3 yr (since Jul 9, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 58 Katrina Ln (Applied)0.43 mi NE
In "Applied" for 8.4 yr (since Jun 12, 2018), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
- New home (Issued)0.25 mi NW
Active in "Issued" for 5.8 yr (first record Jan 29, 2021) with no new permit activity recorded in 5.8 yr.
Entity-resolved builders & contractors in ½ mile: Selvig Development (2 on parcel, 2 in ½ mi · Electrical / panel); True Blue Electric (1 on parcel, 1 in ½ mi · Solar / battery storage); Ernest Ongaro And Sons (1 on parcel, 1 in ½ mi · HVAC / heat pump); J And A Plumbing And Rooter Service (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Owner Builder (11 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 175222 | Windows / doors / siding | Issued | Iss. Oct 16, 2023 | $50,000 | Structural Door & Window Replacement |
| B31553 | HVAC / heat pump | Issued | Iss. Oct 26, 2022 | $6,000 | Replace failed ducting with new ducting — Replace Ductwork |
| 169761 | Solar / battery storage | Issued | Iss. Oct 27, 2021 | $64,191 | 10.36kw Groundmount Photovoltaic & Energy Storage System T.D. 10/25/21 |
| 161610 | Electrical / panel | Issued | Iss. May 23, 2019 | $30,000 | Change A 3 Door Garage Into 2 Door With A Man Door & Lighting Outside. T.D. 5/16/19 |
| B14185 | Plumbing / water heater / sewer | Issued | Iss. Jan 26, 2018 |