40 A Rock Rd
Kentfield 94904 · Kentfield · Unincorporated Marin · Coordinates: 37.95370, -122.55946
Parcel & Assessor
- Lot size:
- 76,099 sq ft (1.75 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 40A ROCK RD; 40 ROCK RD
Zoning & Land Use
RSP-1 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-1, a single-family residential zone. The lot is 76,099 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 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)
HUD Small Area FMR (ZIP 94904) · FY 2026
Studio $2,260 · 1BR $2,710 · 2BR $3,280 · 3BR $4,190 · 4BR $4,340
Nearby Activity (½ mile radius, since October 2024)
23 active or recent development projects (21 housing units across completed, permitted, and pipeline stages) and 303 total building permits recorded within ½ mile.
- New construction16 permits (6 units)
- Adds housing (ADU)9 permits (9 units)
- Demolition7 permits
- Additions & renovations39 permits
- Building systems185 permits
- Repairs17 permits
- Other30 permits
Developments Deserving Closer Investigation & Active Area Builders
- New home at 75 Rock Rd (Issued)420 ft NE
Active in "Issued" for 2.2 yr (first record Aug 27, 2024) with no new permit activity recorded in 17 mo. High-impact scale (1 housing unit, $936,400 declared valuation across 1 permit).
- Accessory dwelling unit at 40 Rock Rd (adu 40a) (Issued)On this parcel
Active in "Issued" for 16 mo (first record Jul 3, 2025) with no new permit activity recorded in 7 mo.
- Accessory dwelling unit at 31 N Ridgewood Rd (adu 31a) (Issued)0.17 mi S
Active in "Issued" for 20 mo (first record Feb 28, 2025) with no new permit activity recorded in 16 mo. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- Accessory dwelling unit at 432 Woodland Rd (Applied)0.3 mi SW
Active in "Applied" for 2.5 yr (first record Apr 12, 2024) with no new permit activity recorded in 2.5 yr. High-impact scale (1 housing unit, $1,250,000 declared valuation across 1 permit).
Permit & Project History on This Parcel (13 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 181346 | Accessory dwelling unit (new or conversion) | Issued | Iss. Mar 25, 2026 | $40,420 | Convert (E) "Live In" (Permitted Under 171878) To (N) A D U |
| 176163 | Solar / battery storage | Issued | Iss. Mar 8, 2024 | $165,000 | 35.26kw Residential Rooftop Photovoltaic & 70kwh Energy Storage System |
| 171883 | General repair | Issued | Iss. Jul 11, 2022 | $85,000 | Retaining Wall, North, Farthest |
| 171882 | General repair | Issued | Iss. Jul 11, 2022 | $100,000 | Retaining Wall, North, Close To Pool |
| 171881 | General repair | Issued | Iss. Jul 11, 2022 | $40,000 | Retaining Wall, North, Close To House |
| 171880 | General repair | Issued | Iss. Jul 11, 2022 | $150,000 | Retaining Wall, West |
| 171879 | Pool / spa | Issued | Iss. Jul 11, 2022 | $400,000 | Pool & Spa |
| 171878 | Remodel / interior alteration | Issued | Iss. Jul 11, 2022 | $3,975,000 | Major Remodel; Addition; Utility Area; Decks K F D K S D |
| 171127 | Demolition | Issued | Iss. Apr 11, 2022 | $20,000 | Demo Of Covered Entry, Decks, Ret Walls, & Pool |
| 170199 | General repair | Issued | Iss. Dec 17, 2021 | $3,000 | Minor Roof Changes Not Including Elevations; Chg Eng Of Record - Related To 155939 |
| 160246 | Remodel / interior alteration | Issued | Iss. Dec 4, 2018 | $90,000 | Kitch Rmdl, Door For Window Same Header***Ext To 12/4/20 Contr Removed Himself 12/2/19 |
| 155939 | Remodel / interior alteration | Issued | Iss. Jul 10, 2017 | $75,000 | Remod Pool House 7/28/16 |
| 155938 | Remodel / interior alteration | Issued | Iss. Jul 10, 2017 | $250,000 | Remodel Main House 8/18/16 |