100 Corte Balboa
Greenbrae 94904 · Kentfield · Unincorporated Marin · Coordinates: 37.95134, -122.53259
Executive Verdict · Public-Records Synthesis
Zoned R1-B2 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,375,000 ($2,090,000–$2,660,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B2 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 13,373 sq ft lot. Local precedent is active with 2 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$16,707 contributory est.)
Public building records show issued construction/renovation work on this parcel (5 total permits, latest Aug 7, 2025).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Kentfield
104 substantial renovation & housing permits over 24 months (41.3 per 1,000 parcels vs. 16.4 citywide baseline) (#7 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Kentfield)
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)
- ! 6 slow or stalled nearby projects within ½ mile
Closest lead: Accessory dwelling unit at 34 Wolfe Grade (0.3 mi NW, 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 (~$27,763/yr at $2,375,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,314/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:
- 13,373 sq ft (0.31 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 100 CORTE BALBOA
Zoning & Land Use
R1-B2 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B2 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B2, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B2, a single-family residential zone. The lot is 13,373 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
- Not in a State-mapped fire hazard severity zone
- FEMA National Flood Hazard Layer
- Zone X: minimal flood hazard (all of the lot) · FIRM panel 06041C0458F, 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: $2,090,000 – $2,660,000 · Status: Off market
HUD Small Area FMR (ZIP 94904) · FY 2026
Studio $2,260 · 1BR $2,710 · 2BR $3,280 · 3BR $4,190 · 4BR $4,340
Developments Deserving Closer Investigation & Active Area Builders
- Accessory dwelling unit at 34 Wolfe Grade (Applied)0.3 mi NW
In "Applied" for 2.8 yr (since Jan 17, 2024), 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, $750,000 declared valuation across 1 permit).
- New commercial building at 675 Sir Francis Drake Blvd (Issued)0.24 mi W
Active in "Issued" for 12.7 yr (first record Mar 6, 2014) with no new permit activity recorded in 12.5 yr. High-impact scale ($2,400,000 declared valuation across 2 permits).
- New home at 33 Bretano Way (Issued)0.31 mi SE
Active in "Issued" for 19 mo (first record Apr 11, 2025) with no new permit activity recorded in 14 mo. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- Demolition at 25 Corte Sereno (Applied)0.24 mi N
In "Applied" for 4.8 yr (since Jan 14, 2022), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
Entity-resolved builders & contractors in ½ mile: Semper Solaris Construction (3 on parcel, 3 in ½ mi · Roof replacement); Semper Solaris (1 on parcel, 1 in ½ mi · Solar / battery storage); Moore Home Services (1 on parcel, 1 in ½ mi · Plumbing / water heater / sewer); Owner Builder (54 in ½ mi · Remodel / interior alteration); Owner (35 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (5 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B43357 | Plumbing / water heater / sewer | Issued | Iss. Aug 7, 2025 | $25,000 | REPLACE SEWER LINE 80FT AND 4IN DIAMETER. — Replace Plumbing Fixtures(s) |
| B26500 | Solar / battery storage | Issued | Iss. Aug 4, 2021 | $2,300 | 1 (N) 125A Meter & Disconnect Main Service Panel to an (E) Solar System — Service Upgrade |
| 168987 | Solar / battery storage | Issued | Iss. Aug 4, 2021 | $28,630 | 4.07 Kw Rooftop Photovoltaic & Energy Storage System - Express |
| B26243 | Roof replacement | Issued | Iss. Jul 7, 2021 | $17,250 | Re Roof--Remove & dispose off existing roofing material, install new roof, re-flash pipes, vent to code. — ReRoofing; Wi… |
| B25733 | Roof replacement |