20 Morning Sun Ave
Mill Valley 94941 · Homestead · Unincorporated Marin · Coordinates: 37.89171, -122.53448
Executive Verdict · Public-Records Synthesis
Zoned R1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,288,000 ($2,013,000–$2,563,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 11,151 sq ft lot. Local precedent is active with 4 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$55,440 contributory est.)
Public building records show issued construction/renovation work on this parcel (7 total permits, latest Mar 25, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Homestead
22 substantial renovation & housing permits over 24 months (20.7 per 1,000 parcels vs. 16.4 citywide baseline) (#2 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Homestead)
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: 2 new homes (0.15 mi NE, issued). 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 (~$26,762/yr at $2,288,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,230/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:
- 11,151 sq ft (0.26 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 20 MORNING SUN AVE
Zoning & Land Use
R1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1, a single-family residential zone. The lot is 11,151 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 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: $2,013,000 – $2,563,000 · 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
- 2 new homes (Issued)0.15 mi NE
Active in "Issued" for 5.7 yr (first record Mar 1, 2021) with no new permit activity recorded in 5.7 yr. High-impact scale (2 housing units, 1 deed-restricted affordable across 0 permits).
- 2 new homes (Issued)0.15 mi NE
Active in "Issued" for 5.7 yr (first record Mar 1, 2021) with no new permit activity recorded in 5.7 yr. High-impact scale (2 housing units, 1 deed-restricted affordable across 0 permits).
- 9 new homes (Issued)0.21 mi N
Active in "Issued" for 5.4 yr (first record Jun 9, 2021) with no new permit activity recorded in 5.4 yr. High-impact scale (9 housing units across 0 permits).
- New commercial building at 100 Harvard Ave (Issued)0.24 mi S
Active in "Issued" for 23 mo (first record Dec 26, 2024) with no new permit activity recorded in 18 mo. High-impact scale ($6,500,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Owner (1 on parcel, 37 in ½ mi · Remodel / interior alteration); Tamalpais Construction (1 on parcel, 4 in ½ mi · Remodel / interior alteration); Renewal By Andersen (2 on parcel, 2 in ½ mi · Windows / doors / siding); Wedge Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Tech Air (1 on parcel, 1 in ½ mi · HVAC / heat pump).
Permit & Project History on This Parcel (7 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B46289 | Roof replacement | Issued | Iss. Mar 25, 2026 | $48,800 | ReRoofing; With Electronic Inspection |
| B35036 | HVAC / heat pump | Issued | Iss. Aug 14, 2023 | $12,000 | Replace gas furnace and add air conditioning — Mechanical Appliance |
| B34953 | Electrical / panel | Issued | Iss. Aug 2, 2023 | $3,000 | Upgrade 100 amp panel to 200 amps — Service Upgrade |
| 172675 | Remodel / interior alteration | Issued | Iss. Nov 3, 2022 | $120,000 | Remodel: Kitchen, Dining Rm, & Family Rm; Replace [E] Doors & Windows |
| 156566 | Windows / doors / siding | Issued | Iss. Sep 21, 2017 |