Mill Valley 94941 · APN 028-153-18 · Mill Valley
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).
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
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)
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)
Automated synthesis of indexed municipal, county, state, and federal public records — informational context only, not a formal appraisal, survey, or legal/tax determination.
Since November 2024 within ½ mile: 4 homes completed, 3 permitted, 10 proposed or in review.
13 projects with a record in this window, grouped by us from permits and State housing reports. Units are as proposed on each project's latest record and counted at its current stage.
95 permits within ½ mile since November 2024
$2,413,000
Benchmark range: $2,051,000 – $2,775,000
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)
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)
The map shows new construction, ADUs, demolitions, additions, and renovations. Routine systems work (roofs, HVAC, water heaters) is counted but not mapped. Unit counts are as stated on permits.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: permits located by parcel, ½ mile radius · Retrieved Nov 13, 2026
Public-records benchmark estimate combining Zillow Home Value Index (Data provided by Zillow), Census ACS 5-year estimates, parcel land-use/lot characteristics, and issued building permits. Not an official appraisal.
We don't have building permits for Mill Valley, so we can't show what has been permitted nearby.
Permit counts, by the date issued (or applied, if not yet issued). Lot splits are planning cases, which we don't have.
We read public zoning and hazard maps against state law (ADUs: Gov. Code 66314; SB 9: Gov. Code 65852.21 and 66411.7). Local rules, title, tenancy history and site conditions can change the answer. Check with Mill Valley's planning department before relying on it.
Sources: County of Marin GIS (MarinMap), Zoning (11 cities and unincorporated Marin) (retrieved Nov 13, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the State Responsibility Area (effective 2024-04-01) (retrieved Nov 9, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the Local Responsibility Area (map dated 2025-03-24) (retrieved Nov 9, 2026) · FEMA, National Flood Hazard Layer — flood hazard zones (retrieved Nov 9, 2026) · FEMA, National Flood Hazard Layer — FIRM panels (retrieved Nov 9, 2026) · California Geological Survey, Alquist-Priolo Earthquake Fault Zones (retrieved Nov 9, 2026) · Zoning classes: our classification of RS-20 as single-family residential, checked against the zone description on Oct 24, 2026
Chronological history of building permit applications and issuances, snapshot-dated status changes, State housing entitlements, surrounding development within ½ mile, and area home-value trends.
Permit issued and active for 3.8 yr (first record Jan 9, 2023), with no completion or new permit record in 3.8 yr. · 1 unit
Permit issued and active for 10.7 yr (first record Mar 7, 2016), with no completion or new permit record in 10.2 yr. · 1 unit · $900,000 declared valuation
Permit issued and active for 9.5 yr (first record May 23, 2017), with no completion or new permit record in 9.5 yr. · 1 unit
In "Entitled" for 8.5 yr (since May 10, 2018), with no new permit record in 8.5 yr. · 1 unit
Permit issued and active for 8.2 yr (first record Aug 28, 2018), with no completion or new permit record in 8.2 yr. · 1 unit
Permit issued and active for 7.4 yr (first record Jun 15, 2019), with no completion or new permit record in 7.4 yr. · 1 unit
Nearby roof replacement (646 Ridgewood Ave): First appeared in published agency feed
Record B49103 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (58 Castle Rock Dr): First appeared in published agency feed
Record B48991 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Latest published Zillow Home Value Index (ZHVI) update
Changed from $1,980,059 in September 2025 to $2,181,389 in September 2026.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94941 (not a parcel appraisal)
409 Montford Ave (Adu 409a) · 1 unit · $75,000 valuation
Records span Jul 2, 2026 to Sep 24, 2026 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
550 Montford Ave · 1 unit · $175,000 valuation
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
1 unit
Records span Oct 13, 2025 to Oct 23, 2025 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Annual ZIP 94941 home-value index checkpoint
Changed from $2,042,452 in September 2024 to $1,980,059 in September 2025.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94941 (not a parcel appraisal)
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
408 Laverne Ave (Adu 408a) · 1 unit · $2,700,000 valuation
Records span Jul 12, 2024 to Aug 29, 2025 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Cross-referenced intelligence from our historical development graph—connecting parcels, permits, entity-resolved builders, empirical review-time distributions, and neighborhood renovation trends.
Explore full Mill Valley development graph →Active in "Issued" for 3.8 yr (first record Jan 9, 2023) with no new permit activity recorded in 3.8 yr.
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).
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).
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).
Active in "Issued" for 2.3 yr (first record Jul 12, 2024) with no new permit activity recorded in 14 mo. High-impact scale (1 housing unit, $2,700,000 declared valuation across 1 permit).
Active in "Entitled" for 13 mo (first record Oct 13, 2025) with no new permit activity recorded in 13 mo. High-impact scale (5 housing units across 0 permits).
HUD Small Area Fair Market Rent · ZIP 94941
HUD FY 2026 · 40th-percentile gross rentCensus ACS 5-year median gross rent (all bedroom counts combined):
Area home-value benchmarks (not an appraisal)
ZIP & neighborhood mediansUnder California Proposition 13, the seller's historical assessed value does not carry over to a buyer. On sale, the parcel is reassessed at the purchase price: 1.00% base rate ($24,150/yr) + local voter-approved bond debt ($3,623/yr) + fixed direct levies/Mello-Roos ($450/yr).
Mapped hazard zone insurance context on this parcel:
Model adding a backyard ADU or garage conversion under California's Prop 13 blended new-construction assessment (existing house & land tax base stays intact; only ADU build cost is assessed) and SB 13 impact-fee rules.
−$141,374/yr
Cash needed: $531,300
NOI: $5,165/yr
P&I: $12,212/mo
For $0/mo net cash flow
At $3,950/mo gross rent
| Scenario | Assumptions | Year 1 Rent | Year 1 Cash Flow | Cash-on-Cash | Break-Even Rent | Year 5 Cash Flow |
|---|---|---|---|---|---|---|
| Conservative | −8% starting rent, +3% vacancy, +3% combined maintenance/CapEx, 1.5%/yr rent growth | $3,634/mo | −$12,235/mo | -27.6% | $20,712/mo | −$12,295/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,950/mo | −$11,781/mo | -26.6% | $19,171/mo | −$11,617/mo |
| Optimistic (cap-limited) | +6% starting rent, 3% vacancy, 4.5%/yr rent growth (capped by AB 1482 ceiling of 8.6%/yr) | $4,187/mo | −$11,521/mo | -26.0% | $18,726/mo | −$11,101/mo |
Rental regulatory context (informational only — not legal advice):
California AB 1482 (Tenant Protection Act, Civ. Code § 1947.12) caps annual rent increases at 5% + local CPI (max 10%) on covered properties.
Issued1 unitsJan 9, 2023 – Jan 9, 2023
We group related permits and State housing reports into projects. That grouping is our inference, not an official record.
No building permits are recorded for this parcel since 2016.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel (APN) · Retrieved Nov 13, 2026 · Received and issued dates come from the County of Marin. The county publishes no final or expired status, so an issued permit stays 'Issued' after the work is done.
| Report year | Project / record | Type | Entitled | Permitted | Completed | Deed-restricted |
|---|---|---|---|---|---|---|
| 2023 | New ADU(B-044066) | ADU · Owner | 1 (Jan 9, 2023) | 1 (Feb 23, 2023) | — | — |
Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: project (parcel) · Retrieved Nov 9, 2026 · From Mill Valley's Housing Element Annual Progress Reports. A project can appear in several report years as it moves from entitlement to permit to completion.
Source: County of Marin GIS (MarinMap), Zoning (11 cities and unincorporated Marin) · Geography: zoning district polygon at parcel point · Retrieved Nov 13, 2026
0.52 acres
Assessor's classification for assessment purposes. This is not zoning.
215 HELENS LN; 405 MARION AVE
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 028-153-18. Assessed value is not market value.
Search by parcel number 028-153-18 (Marin County Tax Collector)
Permits issued in unincorporated Marin in the past 48 months. Each city keeps its own records.
The official flood hazard map for this location. Our reading of it is under What could be built here.
This site does not show owner names.