325 Hidden Valley Ln
San Anselmo 94960 · Sleepy Hollow · Unincorporated Marin · Coordinates: 38.00707, -122.57371
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 $2,030,000 ($1,786,000–$2,274,000).
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 48,395 sq ft lot.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$33,400 contributory est.)
Public building records show issued construction/renovation work on this parcel (4 total permits, latest Sep 2, 2026).
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home at 830 Butterfield Rd (0.27 mi S, 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)
- ! Year 1 Prop 13 tax reset (~$23,795/yr at $2,030,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,983/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:
- 48,395 sq ft (1.11 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 325 HIDDEN VALLEY LN
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 48,395 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: $1,786,000 – $2,274,000 · 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 830 Butterfield Rd (Issued)0.27 mi S
Active in "Issued" for 8.3 yr (first record Aug 9, 2018) with no new permit activity recorded in 7.6 yr. High-impact scale (1 housing unit, $1,097,000 declared valuation across 2 permits).
- Accessory dwelling unit at 990 Butterfield Rd (Applied)0.17 mi W
In "Applied" for 5.8 yr (since Jan 13, 2021), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Demolition at 854 Butterfield Ln (Applied)0.25 mi S
In "Applied" for 2.3 yr (since Aug 1, 2024), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
- Demolition at 111 Deer Hollow Rd (Applied)0.44 mi S
In "Applied" for 6 yr (since Nov 9, 2020), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
Entity-resolved builders & contractors in ½ mile: G Family Construction (1 on parcel, 3 in ½ mi · Addition (adds square footage)); Hci Solar (1 on parcel, 1 in ½ mi · Solar / battery storage); Capstone Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Divine Electric (1 on parcel, 1 in ½ mi · Electrical / panel); Owner Builder (30 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (4 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B48148 | Roof replacement | Issued | Iss. Sep 2, 2026 | $15,050 | ReRoofing |
| 168389 | Solar / battery storage | Issued | Iss. Jun 7, 2021 | $41,254 | 8.84kw Rooftop Photovoltaic & Energy Storage System - Express |
| 166703 | Addition (adds square footage) | Issued | Iss. Dec 29, 2020 | — | (23)(58)(56) Addn, Rmdl, Wndws, Sding |
| B15692 | Electrical / panel | Issued | Iss. Aug 14, 2018 | $6,000 | Main electrical service panel upgrade to 200Amps (ar existing location). — Service Upgrade |