811 Butterfield Rd
San Anselmo 94960 · Sleepy Hollow · Unincorporated Marin · Coordinates: 38.00260, -122.57554
Executive Verdict · Public-Records Synthesis
Zoned R1-BD 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 $2,198,000 ($1,934,000–$2,462,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-BD supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 30,884 sq ft lot. Local precedent is active with 3 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$201,114 contributory est.)
Public building records show issued construction/renovation work on this parcel (10 total permits, latest Apr 28, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Sleepy Hollow
32 substantial renovation & housing permits over 24 months (32.7 per 1,000 parcels vs. 16.4 citywide baseline) (#4 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Sleepy Hollow)
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)
- ! Delayed or open permit activity on this parcel
Demolition (80503): Pending in review for 9.3 yr (61.6× the 55d median) — slower than 90% of demolition permits in Unincorporated Marin (median 55d, 90th pct 261d, n=130).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 2 slow or stalled nearby projects within ½ mile
Closest lead: New home at 666 Fawn Dr (0.49 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)
Parcel & Assessor
- Lot size:
- 30,884 sq ft (0.71 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 811 BUTTERFIELD RD
Zoning & Land Use
R1-BD — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-BD (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-BD, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-BD, a single-family residential zone. The lot is 30,884 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: $1,934,000 – $2,462,000 · Status: Off market
HUD Small Area FMR (ZIP 94960) · FY 2026
Studio $2,510 · 1BR $3,010 · 2BR $3,640 · 3BR $4,650 · 4BR $4,820
Developments Deserving Closer Investigation & Active Area Builders
- New home at 666 Fawn Dr (Applied)0.49 mi E
In "Applied" for 7.5 yr (since Apr 29, 2019), 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, $1,000,000 declared valuation across 1 permit).
- Demolition (80503) (Applied)On this parcel
Pending in review for 9.3 yr (61.6× the 55d median) — slower than 90% of demolition permits in Unincorporated Marin (median 55d, 90th pct 261d, n=130).
- Demolition (80502) (Applied)On this parcel
Pending in review for 9.3 yr (61.6× the 55d median) — slower than 90% of demolition permits in Unincorporated Marin (median 55d, 90th pct 261d, n=130).
- Demolition (80501) (Applied)On this parcel
Pending in review for 9.3 yr (61.6× the 55d median) — slower than 90% of demolition permits in Unincorporated Marin (median 55d, 90th pct 261d, n=130).
Entity-resolved builders & contractors in ½ mile: Owner Builder (4 on parcel, 32 in ½ mi · Remodel / interior alteration); Swan Pools (1 on parcel, 2 in ½ mi · Pool / spa); Tesla Energy Operations (1 on parcel, 1 in ½ mi · Solar / battery storage); Owner (11 in ½ mi · Remodel / interior alteration); Drake Building (5 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (10 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B42184 | Solar / battery storage | Issued | Iss. Apr 28, 2025 | $21,560 | Install (24) roof mount solar panels at 9.84 kW and 1 battery |
| 176717 | Pool / spa | Issued | Iss. May 23, 2024 | $125,000 | Pool W Safety Cover |
| 161487 | General repair | Issued | Iss. May 9, 2019 | $10,000 | Retaining Wall - Upper Yard T.D. 4/12/19 |
| 161486 | Addition (adds square footage) | Issued | Iss. May 9, 2019 | $140,000 | New Mstr Bdrm W/Bth Rm T.D. 4/12/19 |
| 160892 | Demolition | Issued | Iss. Mar 4, 2019 | $5,000 |