1231 Waterview Dr
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.88952, -122.54482
Executive Verdict · Public-Records Synthesis
Zoned RSP-1.5 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,973,000 ($1,736,000–$2,210,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RSP-1.5 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 3,223 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 (+$7,297 contributory est.)
Public building records show issued construction/renovation work on this parcel (3 total permits, latest Mar 8, 2022).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
- ✓ Above-average reinvestment in Tamalpais
50 substantial renovation & housing permits over 24 months (20.5 per 1,000 parcels vs. 16.4 citywide baseline) (#3 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Tamalpais)
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)
- ! CAL FIRE High Fire Hazard Severity Zone (State Responsibility Area) (all of the lot of lot)
Located in a mapped Fire Hazard Severity Zone. Expect Chapter 7A ignition-resistant building standards, defensible-space inspections, and stricter property insurance underwriting.
Source: CAL FIRE FHSZ (map Apr 1, 2024)
- ! Delayed or open permit activity on this parcel
New garage / accessory structure (89592): Pending in review for 4.7 yr (10.4× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 5 slow or stalled nearby projects within ½ mile
Closest lead: New home at 560 Alta Way (0.36 mi SE, 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)
Parcel & Assessor
- Lot size:
- 3,223 sq ft (0.07 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 1231 WATERVIEW DR
Zoning & Land Use
RSP-1.5 — Residential Single Family Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RSP-1.5 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RSP-1.5, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RSP-1.5, a single-family residential zone. The lot is 3,223 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
- High 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 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: $1,736,000 – $2,210,000 · 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
- New home at 560 Alta Way (Applied)0.36 mi SE
In "Applied" for 3.3 yr (since Aug 10, 2023), 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, $975,000 declared valuation across 1 permit).
- New garage / accessory structure (89592) (Applied)On this parcel
Pending in review for 4.7 yr (10.4× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
- New home at 210 Brabo Ter (Issued)0.33 mi NE
Active in "Issued" for 3.1 yr (first record Oct 12, 2023) with no new permit activity recorded in 2.6 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
- New home at 204 Reed St (Issued)0.35 mi NE
Active in "Issued" for 4.3 yr (first record Aug 5, 2022) with no new permit activity recorded in 3.5 yr. High-impact scale (1 housing unit, $950,000 declared valuation across 1 permit).
Entity-resolved builders & contractors in ½ mile: Solar Technologies (1 on parcel, 1 in ½ mi · Solar / battery storage); Ste Electric (1 on parcel, 1 in ½ mi · Electrical / panel); Owner Builder (59 in ½ mi · Remodel / interior alteration); Owner (33 in ½ mi · Remodel / interior alteration); Foley Built (5 in ½ mi · Addition (adds square footage)).
Permit & Project History on This Parcel (3 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 89592 | New garage / accessory structure | Applied | App. Mar 8, 2022 | $130,000 | Expand Living Room; Add Bedroom, Bath And Interior Stair @ Basement; Covered Porch; Deck S M F D M V S D |
| B25146 | Electrical / panel | Issued | Iss. Mar 15, 2021 | $1,200 | 125A to 125A like for like — Service Upgrade |
| 167096 | Solar / battery storage | Issued | Iss. Feb 8, 2021 | $20,270 | 3.27kw Rooftop Photovoltaic |