259 Morning Sun Ave
Mill Valley 94941 · Almonte · Unincorporated Marin · Coordinates: 37.88225, -122.52598
Executive Verdict · Public-Records Synthesis
Zoned R1-B1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,121,000 ($1,866,000–$2,376,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned R1-B1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 5,881 sq ft lot. Local precedent is active with 7 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
- ✓ Documented permitted upgrades (+$43,980 contributory est.)
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Feb 19, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
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)
- ! Delayed or open permit activity on this parcel
Remodel / interior alteration (174650): Issued after 19 mo (7.0× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 3 slow or stalled nearby projects within ½ mile
Closest lead: New home at 334 Dolan Ave (0.22 mi W, 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 (~$24,842/yr at $2,121,000)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,070/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:
- 5,881 sq ft (0.14 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 259 MORNING SUN AVE
Zoning & Land Use
R1-B1 — Residential Single Family (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned R1-B1 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned R1-B1, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned R1-B1, a single-family residential zone. The lot is 5,881 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 06041C0469F, 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: $1,866,000 – $2,376,000 · 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
- Remodel / interior alteration (174650) (Issued)On this parcel
Issued after 19 mo (7.0× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
- Plumbing / water heater / sewer (170711) (Issued)On this parcel
Issued after 12 mo — slower than 90% of plumbing / water heater / sewer permits in Unincorporated Marin (median 0d, 90th pct 0d, n=2,211).
- Remodel / interior alteration (85783) (Applied)On this parcel
Pending in review for 6.4 yr (28.3× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
- New home at 334 Dolan Ave (Issued)0.22 mi W
Active in "Issued" for 8.2 yr (first record Sep 5, 2018) with no new permit activity recorded in 8 yr. High-impact scale (1 housing unit, $759,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Leonardo Construction (3 on parcel, 3 in ½ mi · Plumbing / water heater / sewer); Capstone Roofing (1 on parcel, 1 in ½ mi · Roof replacement); Marin Republic Construction (1 on parcel, 1 in ½ mi · Remodel / interior alteration); Urban Energy (1 on parcel, 1 in ½ mi · Other); Owner Builder (80 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (6 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| B45940 | Other | Issued | Iss. Feb 19, 2026 | $10,000 | — |
| B44781 | Roof replacement | Issued | Iss. Nov 14, 2025 | $16,450 | Remove existing roof. Install with new Lifetime Class A composition shingles. — ReRoofing |
| B40864 | Solar / battery storage | Issued | Iss. Jan 15, 2025 | $5,000 | Install new Solar Panel System on the roof with battery backup |
| 174650 | Remodel / interior alteration | Issued | Iss. Aug 1, 2023 | $75,000 | Remodel 2nd Flr Bath; Replace And Add Deck, Spiral Stair; Replace 2 Windows With Sliding Doors |
| 170711 | Plumbing / water heater / sewer | Issued | Iss. Feb 23, 2022 |