215 Helens Ln
Mill Valley 94941 · Mill Valley · Coordinates: 37.90234, -122.55244
Executive Verdict · Public-Records Synthesis
Zoned RS-20 in Mill Valley with likely ADU & SB 9 infill eligibility and mapped CAL FIRE high fire hazard severity zone (local responsibility area) due diligence; benchmark value $2,413,000 ($2,051,000–$2,775,000).
Upsides & Opportunities
- ✓ ADU & SB 9 infill pathways screen as likely eligible
Zoned RS-20 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 22,564 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Mill Valley zoning · CA Gov. Code 66314 & 65852.21
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 (Local 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 Mar 24, 2025)
- ! Delayed or open permit activity on this parcel
New home: Active in "Issued" for 3.8 yr (first record Jan 9, 2023) with no new permit activity recorded in 3.8 yr.
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 2 Hart Ln (0.24 mi SE, 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)
Parcel & Assessor
- Lot size:
- 22,564 sq ft (0.52 ac)
- Assessor use:
- Single-Resid. - Improved
- Addresses on lot:
- 215 HELENS LN; 405 MARION AVE
Zoning & Land Use
RS-20 — Single Fam Res (min 20,000 SF) (Mill Valley)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RS-20 (single-family residential): state law allows ADUs where homes are allowed.
- SB 9: two homes on the lotLikely eligible
Zoned RS-20, a single-family residential zone.
- SB 9: split into two lotsLikely eligible
Zoned RS-20, a single-family residential zone. The lot is 22,564 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 (Local Responsibility Area) (all of the lot, map Mar 24, 2025)
- 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: $2,051,000 – $2,775,000 · 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
Nearby Activity (½ mile radius, since November 2024)
13 active or recent development projects (17 housing units across completed, permitted, and pipeline stages) and 95 total building permits recorded within ½ mile.
Developments Deserving Closer Investigation & Active Area Builders
- New home (Issued)On this parcel
Active in "Issued" for 3.8 yr (first record Jan 9, 2023) with no new permit activity recorded in 3.8 yr.
- New home at 2 Hart Ln (Issued)0.24 mi SE
Active in "Issued" for 6.9 yr (first record Dec 18, 2019) with no new permit activity recorded in 5.9 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
- New home (Entitled)0.26 mi SE
Active in "Entitled" for 6.3 yr (first record Aug 11, 2020) with no new permit activity recorded in 6.3 yr. High-impact scale (1 housing unit, 1 deed-restricted affordable across 0 permits).
- New home at 420 Laverne Ave (Issued)0.38 mi SE
Active in "Issued" for 8.6 yr (first record Apr 23, 2018) with no new permit activity recorded in 3.8 yr. High-impact scale (1 housing unit, $1,100,000 declared valuation across 1 permit).
Permit & Project History on This Parcel (0 permits, 1 grouped projects)
No building permits recorded on this parcel in our dataset.
State HCD Housing Element APR records on this parcel: 1 entry (report years 2023).