303 Springside Way
Mill Valley 94941 · Tamalpais · Unincorporated Marin · Coordinates: 37.87987, -122.53450
Executive Verdict · Public-Records Synthesis
Zoned RMP-17 in Unincorporated Marin with likely ministerial ADU eligibility and mapped CAL FIRE moderate fire hazard severity zone (local responsibility area) due diligence; benchmark value $1,887,000 ($1,661,000–$2,113,000).
Upsides & Opportunities
- ✓ Ministerial ADU / JADU pathway likely eligible
Zone RMP-17 allows residential use qualifying for ministerial ADU review under state law (7 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
- ✓ 9 documented municipal building permits on file
On-parcel permit history is indexed through Oct 30, 2018, letting you verify roof, HVAC, electrical, or structural work against seller disclosures.
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 Moderate 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
Electrical / panel (160006): Issued after 3 mo — slower than 90% of electrical / panel permits in Unincorporated Marin (median 0d, 90th pct 2d, n=3,019).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
- ! 1 slow or stalled nearby project within ½ mile
Closest lead: Accessory dwelling unit at 403 Marin Ave (adu 403a) (0.15 mi SW, 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:
- 1,350 sq ft (0.03 ac)
- Assessor use:
- Single Family Attached
- Addresses on lot:
- 303 SPRINGSIDE WAY
Zoning & Land Use
RMP-17 — Residential Multiple Planned (Unincorporated Marin)
State Housing Pathways Screen (ADU & SB 9)
- ADU or junior ADULikely eligible
Zoned RMP-17 (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 RMP-17 (multifamily residential), not a single-family residential zone.
- SB 9: split into two lotsUnlikely
Zoned RMP-17 (multifamily residential), not a single-family residential zone.
Mapped Hazard Zones on This Lot
- CAL FIRE Fire Hazard Severity Zone
- Moderate 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: $1,661,000 – $2,113,000 · 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
- Electrical / panel (160006) (Issued)On this parcel
Issued after 3 mo — slower than 90% of electrical / panel permits in Unincorporated Marin (median 0d, 90th pct 2d, n=3,019).
- Electrical / panel (160005) (Issued)On this parcel
Issued after 3 mo — slower than 90% of electrical / panel permits in Unincorporated Marin (median 0d, 90th pct 2d, n=3,019).
- Electrical / panel (160004) (Issued)On this parcel
Issued after 3 mo — slower than 90% of electrical / panel permits in Unincorporated Marin (median 0d, 90th pct 2d, n=3,019).
- Electrical / panel (160003) (Issued)On this parcel
Issued after 3 mo — slower than 90% of electrical / panel permits in Unincorporated Marin (median 0d, 90th pct 2d, n=3,019).
Entity-resolved builders & contractors in ½ mile: Flores Builders (5 on parcel, 5 in ½ mi · Electrical / panel); Mill Valley Builders (2 on parcel, 2 in ½ mi · General repair); Mcleran (1 on parcel, 1 in ½ mi · Roof replacement); Owner Builder (103 in ½ mi · Remodel / interior alteration); Owner (59 in ½ mi · Remodel / interior alteration).
Permit & Project History on This Parcel (9 permits, 0 grouped projects)
| Record # | Category | Status | Applied / Issued | Valuation | Description |
|---|---|---|---|---|---|
| 160006 | Electrical / panel | Issued | Iss. Oct 30, 2018 | $20,000 | Rot Repairs; Siding; Possible Electrical & Windows T.D. 8/30/18 |
| 160005 | Electrical / panel | Issued | Iss. Oct 30, 2018 | $20,000 | Rot Repairs; Siding; Possible Electrical & Windows T.D. 8/30/18 |
| 160004 | Electrical / panel | Issued | Iss. Oct 30, 2018 | $20,000 | Rot Repairs; Siding; Possible Electrical & Windows T.D. 8/30/18 |
| 160003 | Electrical / panel | Issued | Iss. Oct 30, 2018 | $10,000 | Rot Repairs; Siding; Possible Electrical & Windows T.D. 8/30/18 |
| 83991 | Electrical / panel | Applied | App. Aug 1, 2018 |