31 A Erin Dr
San Rafael 94903 · Marinwood · Unincorporated Marin · Coordinates: 38.02668, -122.54446
Executive Verdict · Public-Records Synthesis
Zoned RMP-1.38 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,644,000 ($1,447,000–$1,841,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-1.38 allows residential use qualifying for ministerial ADU review under state law (12 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$257,280 contributory est.)
Public building records show issued construction/renovation work on this parcel (3 total permits, latest Apr 28, 2025).
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 High 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)
- ! Delayed or open permit activity on this parcel
Accessory dwelling unit at 31 Erin Dr (31a) - Lot: Active in "Issued" for 3.1 yr (first record Sep 29, 2023) with no new permit activity recorded in 20 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 5 slow or stalled nearby projects within ½ mile
Closest lead: New home at 118 Erin Ct (0.12 mi NW, 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)
Parcel & Assessor
- Lot size:
- 22,346 sq ft (0.51 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 31A ERIN DR; 31 ERIN DR
Zoning & Land Use
RMP-1.38 — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-1.38 (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-1.38 (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-1.38 (multifamily residential), not a single-family residential zone.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- High 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 06041C0293E, 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: $1,447,000 – $1,841,000 · Status: Off market
HUD Small Area FMR (ZIP 94903) · FY 2026
Studio $2,880 · 1BR $3,450 · 2BR $4,180 · 3BR $5,340 · 4BR $5,530
Developments Deserving Closer Investigation & Active Area Builders
- Accessory dwelling unit at 31 Erin Dr (31a) - Lot (Issued)On this parcel
Active in "Issued" for 3.1 yr (first record Sep 29, 2023) with no new permit activity recorded in 20 mo.
- New home at 118 Erin Ct (Applied)0.12 mi NW
In "Applied" for 3 yr (since Nov 28, 2023), 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, $55,415,888 declared valuation across 1 permit).
- New home at 115 Erin Ct (Applied)0.13 mi NW
In "Applied" for 3 yr (since Nov 28, 2023), 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, $55,415,888 declared valuation across 1 permit).
- New home at 111 Erin Ct (Applied)0.13 mi NW
In "Applied" for 3 yr (since Nov 28, 2023), 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, $56,632,994 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Haven Construction (2 on parcel, 17 in ½ mi · Accessory dwelling unit (new or conversion)); Secutech (1 on parcel, 1 in ½ mi · Solar / battery storage); Owner Builder (13 in ½ mi · New garage / accessory structure); Owner (7 in ½ mi · Remodel / interior alteration); Hsc Services (3 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (3 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B42189 | Solar / battery storage | Issued | Iss. Apr 28, 2025 | $8,000 | Rooftop mounted PV system 4.05kw |
| 178907 | Accessory dwelling unit (new or conversion) | Issued | Iss. Mar 26, 2025 | $616,292 | S F D, A D U, Garage, Decks Plan 1 B |
| 178471 | General repair | Issued | Iss. Jan 17, 2025 | $36,960 | Retaining Walls |
State HCD Housing Element APR records on this parcel: 1 entry (report years 2025).