40 Arroyo Rd
Forest Knolls 94938 · Forest Knolls · Unincorporated Marin · Coordinates: 38.01640, -122.69272
Executive Verdict · Public-Records Synthesis
Zoned RA-B4-SGV in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,129,000 ($994,000–$1,264,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RA-B4-SGV allows residential use qualifying for ministerial ADU review under state law (1 ADU permit permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ 5 documented municipal building permits on file
On-parcel permit history is indexed through Feb 2, 2015, 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 (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
New home at 42 Arroyo Rd: Active in "Issued" for 12.3 yr (first record Aug 11, 2014) with no new permit activity recorded in 11.8 yr.
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: Demolition at 6956 Sir Francis Drake Blvd (500 ft SE, 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)
Parcel & Assessor
- Lot size:
- 46,609 sq ft (1.07 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 40 ARROYO RD; 42 ARROYO RD
Zoning & Land Use
RA-B4-SGV — Residential Agriculture (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RA-B4-SGV (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotCan't tell
Zoned RA-B4-SGV (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
- SB 9: split into two lotsCan't tell
Zoned RA-B4-SGV (single-family residential): we can't tell whether it counts as a single-family zone for SB 9. Residential agriculture, estate and restricted: large-lot residential; confirm SB 9 with the county.
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 06041C0275D, 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: $994,000 – $1,264,000 · Status: Off market
HUD Small Area FMR (ZIP 94938) · FY 2026
Studio $2,170 · 1BR $2,610 · 2BR $3,150 · 3BR $4,020 · 4BR $4,200
Developments Deserving Closer Investigation & Active Area Builders
- New home at 42 Arroyo Rd (Issued)On this parcel
Active in "Issued" for 12.3 yr (first record Aug 11, 2014) with no new permit activity recorded in 11.8 yr.
- General repair (71556) (Applied)On this parcel
Pending in review for 12.3 yr (53.9× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
- New garage / accessory structure (71554) (Applied)On this parcel
Pending in review for 12.3 yr (27.3× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
- Demolition at 6956 Sir Francis Drake Blvd (Issued)500 ft SE
Active in "Issued" for 2.8 yr (first record Jan 10, 2024) with no new permit activity recorded in 2.7 yr.
Entity-resolved builders & contractors in ½ mile: Hope Construction (1 on parcel, 1 in ½ mi · New single-family home); Rt Wilson Plumbing (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Daunell David (1 on parcel, 1 in ½ mi · Electrical / panel); Owner Builder (10 in ½ mi · Accessory dwelling unit (new or conversion)); Owner (7 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (5 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 145675 | New single-family home | Issued | Iss. Feb 2, 2015 | $222,000 | New Sfd With Porch & Laundry T.D. 11/19/14 |
| 144193 | Plumbing / water heater / sewer | Issued | Iss. Sep 18, 2014 | $4,500 | Upgrade Water Service |
| 144079 | Electrical / panel | Issued | Iss. Sep 10, 2014 | $3,000 | Relocate Main Meter Service & Underground Sub-Panel |
| 71556 | General repair | Applied | App. Aug 11, 2014 | $5,000 | Ret Wall @ Terrace ( T.D. 11/19/14 (Not Needed 1/26/15 |