20 Chaparro Ave
Lagunitas 94938 · Lagunitas · Unincorporated Marin · Coordinates: 38.01751, -122.70395
Executive Verdict · Public-Records Synthesis
Zoned R1-B3-SGV in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,038,000 ($913,000–$1,163,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B3-SGV supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 6,534 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$18,360 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Aug 3, 2026).
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: New home (60 ft NW, 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 (~$12,387/yr at $1,038,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$1,032/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:
- 6,534 sq ft (0.15 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 20 CHAPARRO AVE
Zoning & Land Use
R1-B3-SGV — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B3-SGV (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B3-SGV, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B3-SGV, a single-family residential zone. The lot is 6,534 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
- 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: $913,000 – $1,163,000 · 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 (Entitled)60 ft NW
In "Entitled" for 2.1 yr (since Oct 4, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- Accessory dwelling unit at 5 Barranca Rd (Applied)0.32 mi NE
In "Applied" for 7.8 yr (since Feb 7, 2019), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
- New home at 152 Alta Ave (Issued)0.13 mi S
Active in "Issued" for 19 mo (first record Apr 1, 2025) with no new permit activity recorded in 14 mo.
- New home at 338 Arroyo Rd (Issued)0.21 mi NW
Active in "Issued" for 12.5 yr (first record Apr 28, 2014) with no new permit activity recorded in 11.6 yr.
Entity-resolved builders & contractors in ½ mile: Owner (1 on parcel, 6 in ½ mi · Addition (adds square footage)); American Solar (1 on parcel, 1 in ½ mi · Solar / battery storage); Simply Solar (1 on parcel, 1 in ½ mi · Solar / battery storage); B Side (1 on parcel, 1 in ½ mi · Windows / doors / siding); Greenwood Electric (1 on parcel, 1 in ½ mi · Electrical / panel).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B47733 | Windows / doors / siding | Issued | Iss. Aug 3, 2026 | $20,000 | Siding Replacement, Non-structural Door/Window Replacement |
| B33246 | Solar / battery storage | Issued | Iss. Mar 31, 2023 | $22,500 | RESIDENTIAL ESS INSTALLATION, GRID TIED, BATTERY BACKUP, NEW PROTECTED LOADSPANEL. |
| B32719 | HVAC / heat pump | Issued | Iss. Feb 25, 2023 | $15,600 | Installed electric forced air handler LG Heat Pump Model # LV361HV4 — Replace Mechanical Appliance |
| B28974 | Electrical / panel | Issued | Iss. Mar 7, 2022 | $7,500 | Replace existing 200 amp meter main service with new 200 amp meter main service — Service Upgrade |
| B28512 | Solar / battery storage |