513 Brookline Way
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.88308, -122.54385
Executive Verdict · Public-Records Synthesis
Zoned RA-B2 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $2,177,000 ($1,916,000–$2,438,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RA-B2 allows residential use qualifying for ministerial ADU review under state law (4 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ Documented permitted upgrades (+$20,592 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Feb 23, 2024).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Tamalpais
50 substantial renovation & housing permits over 24 months (20.5 per 1,000 parcels vs. 16.3 citywide baseline) (#3 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Tamalpais)
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 at 560 Alta Way (0.24 mi NE, 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)
- ! Year 1 Prop 13 tax reset (~$25,486/yr at $2,177,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,124/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:
- 10,237 sq ft (0.24 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 513 BROOKLINE WAY
Zoning & Land Use
RA-B2 — Residential Agriculture (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RA-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotCan't tell
Zoned RA-B2 (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-B2 (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 06041C0468F, effective March 16, 2016
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
Range: $1,916,000 – $2,438,000 · Status: Off market
HUD Small Area FMR (ZIP 94941) · FY 2026
Studio $2,730 · 1BR $3,270 · 2BR $3,960 · 3BR $5,060 · 4BR $5,240
Developments Deserving Closer Investigation & Active Area Builders
- New home at 560 Alta Way (Applied)0.24 mi NE
In "Applied" for 3.3 yr (since Aug 10, 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, $975,000 declared valuation across 1 permit).
- New home at 510 Browning Ct (Issued)0.25 mi E
Active in "Issued" for 10.2 yr (first record Aug 15, 2016) with no new permit activity recorded in 9.9 yr. High-impact scale (1 housing unit, $900,000 declared valuation across 1 permit).
- New home at 731 Bay Rd (Issued)0.35 mi SE
Active in "Issued" for 18 mo (first record May 12, 2025) with no new permit activity recorded in 15 mo. High-impact scale (1 housing unit, $955,000 declared valuation across 1 permit).
- New home at 760 Bay Rd (Issued)0.43 mi S
Active in "Issued" for 9.4 yr (first record Jun 12, 2017) with no new permit activity recorded in 8.4 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Owner Builder (1 on parcel, 67 in ½ mi · Remodel / interior alteration); Sustainable Living Builders (1 on parcel, 1 in ½ mi · Solar / battery storage); Njg Enterprises Dba Nor Cal Ram Jack (1 on parcel, 1 in ½ mi · General repair); Auto Charge Electric (1 on parcel, 1 in ½ mi · Electrical / panel); Manuel Ricardo Zapata (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B37044 | HVAC / heat pump | Issued | Iss. Feb 23, 2024 | $5,786 | INSTALL 65GAL HEAT PUMP WATER HEATER, RUN NEW 220V CIRCUIT FROM MAIN PANEL TO WATER HEATER — New Circuits / Outlets; Rep… |
| B36441 | Electrical / panel | Issued | Iss. Dec 15, 2023 | $5,900 | Replace and upgrade main panel — Service Upgrade |
| B35337 | Solar / battery storage | Issued | Iss. Sep 11, 2023 | $76,880 | Installing 33 panel solar system (13.2 kW), also installing two batteries equalling 27 kWh. |
| 172136 | General repair | Issued | Iss. Aug 15, 2022 | $34,115 | Foundation Repair: Underpinning-Installation Of Five Helical Piles |
| 162475 | Remodel / interior alteration | Issued |