255 Roundtree Way
San Rafael 94903 · Marinwood · Unincorporated Marin · Coordinates: 38.03137, -122.54227
Executive Verdict · Public-Records Synthesis
Zoned RMP-11.8 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE high fire hazard severity zone (local responsibility area) due diligence; benchmark value $1,255,000 ($1,104,000–$1,406,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-11.8 allows residential use qualifying for ministerial ADU review under state law (2 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ 2 documented municipal building permits on file
On-parcel permit history is indexed through Jun 5, 2026, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
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 (Local 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 Mar 24, 2025)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: 125 new homes (0.48 mi N, entitled). 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 (~$14,883/yr at $1,255,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,240/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:
- 697 sq ft (0.02 ac)
- Assessor use:
- Single Family Attached
- Addresses on lot:
- 255 ROUNDTREE WAY
Zoning & Land Use
RMP-11.8 — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-11.8 (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-11.8 (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-11.8 (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 (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0291D, 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: $1,104,000 – $1,406,000 · 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
Nearby Activity (½ mile radius, since November 2024)
20 active or recent development projects (143 housing units across completed, permitted, and pipeline stages) and 509 total building permits recorded within ½ mile.
- New construction21 permits (6 units)
- Adds housing (ADU)12 permits (12 units)
- Demolition2 permits
- Additions & renovations18 permits
- Building systems363 permits
- Repairs52 permits
- Other41 permits
Developments Deserving Closer Investigation & Active Area Builders
- 125 new homes (Entitled)0.48 mi N
In "Entitled" for 23 mo (since Dec 6, 2024), exceeding the 292d median and 313d 90th percentile for new multifamily / condos / mixed-use permits in Unincorporated Marin (n=21). High-impact scale (125 housing units, 124 deed-restricted affordable across 0 permits).
- New home at 115 Erin Ct (Applied)0.29 mi SW
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)0.29 mi SW
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).
- New home at 3 Erin Dr (Applied)0.29 mi SW
In "Applied" for 3 yr (since Oct 31, 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, $2,993,758 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Cal Coast Window And Door (1 on parcel, 1 in ½ mi · Windows / doors / siding); Window And Door Factory Of California (1 on parcel, 1 in ½ mi · Windows / doors / siding); Owner Builder (34 in ½ mi · Remodel / interior alteration); Owner (18 in ½ mi · Remodel / interior alteration); Haven Construction (16 in ½ mi · Accessory dwelling unit (new or conversion)).
Permit & Project History on This Parcel (2 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B47050 | Windows / doors / siding | Issued | Iss. Jun 5, 2026 | $16,888 | Non-structural Door/Window Replacement |
| B24788 | Windows / doors / siding | Issued | Iss. Feb 3, 2021 | $4,000 | Replace 1 patio door and 1 window like for like. — Non-structural Door/Window Replacement |