4345 20th St
San Francisco · Castro/Upper Market · San Francisco · Coordinates: 37.75736, -122.43654
Parcel & Assessor
- Lot size:
- —
- Assessor use:
- —
- Addresses on lot:
- 4345 20TH ST; 4347 20TH ST
Zoning & Land Use
RH-3 — RESIDENTIAL- HOUSE, THREE FAMILY (Residential)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RH-3 (multifamily residential): state law allows ADUs where homes are allowed. On a multifamily lot the state allowance is different: ADUs in non-living space of the building, plus up to eight detached ADUs.
- SB 9: two homes on the lotUnlikely
Zoned RH-3 (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RH-3 (multifamily residential), not a single-family residential zone.
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 0602980118A, effective March 23, 2021
- CGS Alquist-Priolo Earthquake Fault Zone
- Not in an Alquist-Priolo Earthquake Fault Zone
Surrounding Rent & Value Benchmarks (Public Records)
HUD Metro FMR (San Francisco, CA HUD Metro FMR Area) · FY 2026
Studio $2,485 · 1BR $2,977 · 2BR $3,604 · 3BR $4,604 · 4BR $4,772
Nearby Activity (½ mile radius, since October 2024)
40 active or recent development projects (59 housing units across completed, permitted, and pipeline stages) and 1,628 total building permits recorded within ½ mile.
- New construction5 permits (13 units)
- Adds housing (ADU)27 permits (38 units)
- Demolition5 permits
- Additions & renovations593 permits
Permit & Project History on This Parcel (3 permits, 1 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 202606102904 | Accessory dwelling unit (new or conversion) | filed | App. Aug 7, 2026 | $220,000 | legalization udu on 1/f and addition of state adu at basement lvl. excavate (e) slab and add (n),convert into habitable … |
| 202604280247 | Repair tied to a housing/code case | complete | Iss. Apr 28, 2026 | $3,500 | to comply with nov# 202653232: repair deck and stairs, <50%, not street visible. |
| 202405232836 | Windows / doors / siding | complete | Iss. May 29, 2024 | $94,114 | replace (3) windows with retrofit vinyl windows. not street visible. u-factor <0.30. |