340 Marion Ave

Mill Valley 94941 · APN 028-135-10 · Mill Valley

Property brief (PDF)Timeline ↓Calculator ↓Official records ↓

We don't have building permits for Mill Valley, so permit history and nearby activity are incomplete here. Building permits cover unincorporated Marin only; Marin's 11 cities don't publish theirs. New housing in every city comes from the state's Housing Element reports. Parcel, assessor, and record links still apply.

What's changing nearby

Since October 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.

101 permits within ½ mile since October 2024

New construction3
Adds housing (ADU)3 · 3 units
Additions & renovations7
Building systems66
Repairs7
Other15

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.

Explore projects on the map →Explore sales & prices →

Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: permits located by parcel, ½ mile radius · Retrieved Oct 31, 2026

Estimated price, listing status & sales records

Benchmark valuation & transaction history

Estimated PriceArea benchmark

$2,239,000

Benchmark range: $1,903,000 – $2,575,000

Listing StatusOff Market

Not currently listed for sale

Compare nearby sales & prices on map →

Last Sold & Tax Roll

No deed price in open GIS feed

Verify on Assessor's property search

How this estimated price is calculated (Area ZHVI + ACS + Permit Benchmark)

Model monthly ownership cost ↓

1. Area home value baseline: ZIP 94941 Zillow Home Value Index ($2,181,389, September 2026); $2,181,389
2. Parcel & lot adjustment (1.03×): Single-family lot (8,364 sq ft, +2.7% lot-size adjustment vs 6,000 sq ft standard lot); +$57,969
3. Documented permitted improvements: No recent value-adding ADU, addition, or remodel permits recorded on this parcel; +$0

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.

What could be built here

A screen, not a determination

ADU or junior ADU

Likely eligible

Zoned RS-20 (single-family residential): state law allows ADUs where homes are allowed.

What we couldn't check (4)

Setbacks, height and size limits in the local ADU ordinance
Utility and sewer capacity, fire access
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

SB 9: two homes on the lot

Likely eligible

Zoned RS-20, a single-family residential zone.

What we couldn't check (6)

Whether a tenant lived there in the last 3 years, or the building was withdrawn from rent under the Ellis Act
Rent-controlled or deed-restricted affordable housing on the lot
Wetlands, habitat, farmland, hazardous waste sites and conservation easements
Local SB 9 standards (size, setbacks, parking)
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

SB 9: split into two lots

Likely eligible

Zoned RS-20, a single-family residential zone.
The lot is 8,364 sq ft by the assessor, room for two lots of at least 1,200 sq ft, each at least 40% of the original.

What we couldn't check (6)

Owner-occupancy: the applicant must sign an affidavit to live in one of the homes for 3 years
Whether the lot was created by an earlier SB 9 split, or the owner split an adjacent lot
Whether a tenant lived there in the last 3 years, or the building was withdrawn from rent under the Ellis Act
Wetlands, habitat, farmland, hazardous waste sites and conservation easements
Historic district or landmark status: we have no historic layer for this area yet.
Locally adopted fire hazard maps, which can be broader than the State's.

Mapped hazards on this lot

Fire hazard severity zone: High Fire Hazard Severity Zone (Local Responsibility Area), all of the lot · State map of Mar 24, 2025; takes effect when the city or county adopts it
FEMA flood zone: Zone X: minimal flood hazardFIRM panel 06041C0468F, effective March 16, 2016. Official flood map
Earthquake fault zone: Not in an Alquist-Priolo Earthquake Fault Zone

Built nearby: within ¼ mile since October 2023

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 Oct 31, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the State Responsibility Area (effective 2024-04-01) (retrieved Oct 26, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the Local Responsibility Area (map dated 2025-03-24) (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — flood hazard zones (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — FIRM panels (retrieved Oct 26, 2026) · California Geological Survey, Alquist-Priolo Earthquake Fault Zones (retrieved Oct 26, 2026) · Zoning classes: our classification of RS-20 as single-family residential, checked against the zone description on Oct 24, 2026

Property & area intelligence timeline

66 events · 34 slow/stalled projects

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.

Slow-moving or stalled projects (34)

Active projects spending 12+ months pre-issuance, 24+ months under construction, or 6+ months without new records

StalledJADU Convert UnconditionedIssued
On this parcel
Permit issued and active for 2.7 yr (first record Feb 15, 2024), with no completion or new permit record in 2.7 yr. · 1 unit
StalledNew home at 409 Montford AveIssued
0.46 mi SE
Permit issued and active for 12.4 yr (first record Jun 17, 2014), with no completion or new permit record in 12.1 yr. · 1 unit · $1,100,000 declared valuation
StalledNew home at 664 Amaranth BlIssued
0.43 mi SW
Permit issued and active for 12.1 yr (first record Oct 7, 2014), with no completion or new permit record in 11.2 yr. · 1 unit · $500,000 declared valuation
StalledNew homeIssued
0.49 mi NE
Permit issued and active for 9.4 yr (first record May 23, 2017), with no completion or new permit record in 9.4 yr. · 1 unit
StalledNew homeIssued
0.5 mi NW
Permit issued and active for 9.1 yr (first record Sep 15, 2017), with no completion or new permit record in 9.1 yr. · 1 unit
StalledNew homeEntitled
0.47 mi E
In "Entitled" for 8.5 yr (since May 10, 2018), with no new permit record in 8.5 yr. · 1 unit

20263 events

September 2026Market trend
ZIP 94941
ZIP 94941 typical home value: $2,181,389 (+10.2% year-over-year)
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)
Sep 24, 2026Nearby project · Issued
0.46 mi SE
Accessory dwelling unit at 409 Montford Ave (adu 409a) — Issued
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)
May 8, 2026Nearby project · Applied
0.24 mi S
Accessory dwelling unit at 550 Montford Ave — Applied
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)

202511 events

Dec 11, 2025Nearby project · Entitled
0.11 mi N
New home — Entitled
1 unit
⏱ Slow turnaround:In "Entitled" for 11 mo (since Dec 11, 2025), with no new permit record in 11 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Dec 3, 2025Nearby project · Finaled / completed
0.42 mi SE
Detached ADU — Finaled / completed
1 unit
Records span Nov 8, 2023 to Dec 3, 2025 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Oct 23, 2025Nearby project · Entitled
480 ft S
SB9 Lot Split withSFR and ADU — Entitled
1 unit
Records span Oct 13, 2025 to Oct 23, 2025 (0 permits).
⏱ Slow turnaround:In "Entitled" for 13 mo (since Oct 13, 2025), with no new permit record in 12 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Oct 21, 2025Nearby project · Entitled
0.46 mi N
New home — Entitled
1 unit
⏱ Slow turnaround:In "Entitled" for 12 mo (since Oct 21, 2025), with no new permit record in 12 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Oct 13, 2025Nearby project · Entitled
0.47 mi NE
MFR/Office Overlay — Entitled
5 units
⏱ Slow turnaround:In "Entitled" for 13 mo (since Oct 13, 2025), with no new permit record in 13 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
September 2025Market trend
ZIP 94941
ZIP 94941 typical home value: $1,980,059 (−3.1% year-over-year)
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)
Sep 3, 2025Nearby project · Entitled
510 ft N
New home — Entitled
1 unit
⏱ Slow turnaround:In "Entitled" for 14 mo (since Sep 3, 2025), with no new permit record in 14 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Aug 29, 2025Nearby project · Issued
0.47 mi SE
Accessory dwelling unit at 408 Laverne Ave (adu 408a) — Issued
408 Laverne Ave (Adu 408a) · 1 unit · $2,700,000 valuation
Records span Jul 12, 2024 to Aug 29, 2025 (1 permit).
⏱ Slow turnaround:Permit issued and active for 2.3 yr (first record Jul 12, 2024), with no completion or new permit record in 14 mo.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Aug 19, 2025Nearby project · Finaled / completed
0.35 mi N
Attached ADU — Finaled / completed
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
May 5, 2025Nearby project · Finaled / completed
0.28 mi N
Convsersion JADU — Finaled / completed
1 unit
Records span Jun 3, 2024 to May 5, 2025 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
May 1, 2025Nearby project · Issued
430 ft SW
Detached ADU — Issued
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)

20241 event

Nov 19, 2024Nearby project · Finaled / completed
0.31 mi N
ADU Conversion — Finaled / completed
1 unit
Records span May 30, 2023 to Nov 19, 2024 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)

Showing 15 of 66 timeline events

Recorded sales & deed transfers: California county recorders do not publish open bulk deed-transfer feeds without owner-PII restrictions, so individual sale deeds are not redistributed here. For official assessment roll and recorded transfer history in Mill Valley, inspect Assessor's property search ↗.

Development graph & closer investigation

6 investigation leads

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 →

Developments deserving closer investigation (6)

On this parcel & within ½ mile

JADU Convert UnconditionedIssuedNo new record in 2.7 yr
On this parcel
Active in "Issued" for 2.7 yr (first record Feb 15, 2024) with no new permit activity recorded in 2.7 yr.
New home at 2 Hart LnIssuedNo new record in 5.8 yr$750,000
0.35 mi SE
Active in "Issued" for 6.9 yr (first record Dec 18, 2019) with no new permit activity recorded in 5.8 yr. High-impact scale (1 housing unit, $750,000 declared valuation across 1 permit).
New homeEntitledNo new record in 6.2 yr$0
0.36 mi SE
Active in "Entitled" for 6.2 yr (first record Aug 11, 2020) with no new permit activity recorded in 6.2 yr. High-impact scale (1 housing unit, 1 deed-restricted affordable across 0 permits).
New home at 420 Laverne AveIssuedNo new record in 3.7 yr$1,100,000
0.46 mi SE
Active in "Issued" for 8.5 yr (first record Apr 23, 2018) with no new permit activity recorded in 3.7 yr. High-impact scale (1 housing unit, $1,100,000 declared valuation across 1 permit).
New home at 409 Montford AveIssuedNo new record in 12.1 yr$1,100,000
0.46 mi SE
Active in "Issued" for 12.4 yr (first record Jun 17, 2014) with no new permit activity recorded in 12.1 yr. High-impact scale (1 housing unit, $1,100,000 declared valuation across 2 permits).
MFR/Office OverlayEntitledNo new record in 13 mo5 units
0.47 mi NE
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).

Ownership & rental scenario calculator

Prop 13 tax estimate & area benchmarks

Area rent & home-value benchmarks (kept separate from your assumptions)

Click any benchmark to pre-fill the calculator

HUD Small Area Fair Market Rent · ZIP 94941

HUD FY 2026 · 40th-percentile gross rent

Census ACS 5-year median gross rent (all bedroom counts combined):

ZIP 94941$3,100±$331

Area home-value benchmarks (not an appraisal)

ZIP & neighborhood medians

Zillow ZHVI · ZIP 94941(as of September 2026)Data provided by Zillow · typical mid-tier home value in ZIP

$2,181,389

ACS Median Home Value · ZIP 94941Census ACS 2020–2024 owner-occupied self-reported median

$2,000,000+

1. Purchase, financing & Prop 13 tax reassessment

Purchase price ($)Down payment (%)$448,000Interest rate (%)Loan termClosing costs (%)$44,800

Prop 13 post-purchase property tax estimate

$2,184/mo ($26,210/yr · 1.17%)

Under 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 ($22,400/yr) + local voter-approved bond debt ($3,360/yr) + fixed direct levies/Mello-Roos ($450/yr).

Voter bond rate (%)$3,360/yrDirect levies / Mello-Roos ($/yr)Check Assessor's property search ↗

2. Your rent & operating assumptions

Monthly gross rent ($)Your assumptionVacancy allowance (%)−$198/moManagement (%)$300/moMaintenance (%)$198/moCapEx reserve (%)$198/moInsurance ($/mo)$3,300/yrHOA dues ($/mo)Owner utilities ($/mo)

Mapped hazard zone insurance context on this parcel:

Parcel intersects a mapped High Fire Hazard Severity Zone (Local Responsibility Area) (local responsibility area). Properties in High or Very High fire hazard zones may require California FAIR Plan + difference-in-conditions (DIC) coverage; verify actual insurability and quotes early.

3. Scenario results (based on your assumptions)

Net monthly cash flow: −$10,729
Cash-on-cash return: -26.1%
Cap rate (Year 1 NOI): 0.32%
DSCR (NOI / debt): 0.05x
Break-even gross rent: $17,811/mo
Break-even vacancy: 0% (negative at full occ.)

Monthly cash-flow breakdown (Effective gross $3,753 − Operating $3,154 − Debt $11,327)

Gross scheduled rent$3,950

Vacancy allowance (5%)−$198

Effective gross income$3,753

Prop 13 property tax (1.17%)−$2,184

Property insurance−$275

Management (8%), maintenance (5%) & CapEx (5%)−$695

Net Operating Income (NOI)+$598

Mortgage principal & interest (1,792,000 loan)−$11,327

Net monthly cash flow−$10,729

4. Sensitivity & rent-stabilization ceiling (Mill Valley)

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	−$11,182/mo	-27.2%	$19,243/mo	−$11,228/mo
Base (your inputs)	Your entered assumptions, 3.0%/yr rent growth	$3,950/mo	−$10,729/mo	-26.1%	$17,811/mo	−$10,550/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	−$10,468/mo	-25.5%	$17,398/mo	−$10,035/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.

Common statutory exemption signals under AB 1482

Housing issued a certificate of occupancy within the last 15 years (rolling exemption under AB 1482).
Separately alienable single-family homes or condominiums not owned by a corporation, REIT, or LLC with a corporate member (when required statutory notice is in the lease).
Owner-occupied duplexes where the owner occupied one unit from the start of the tenancy.

Development projects on this parcel

JADU Convert Unconditioned
Issued1 unitsFeb 15, 2024 – Feb 15, 2024

We group related permits and State housing reports into projects. That grouping is our inference, not an official record.

Permit history on this parcel

0 records

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 Oct 31, 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.

Housing activity reported to the State

Report year	Project / record	Type	Entitled	Permitted	Completed	Deed-restricted
2024	JADU Convert Unconditioned(B-046603)	ADU · Renter	1 (Feb 15, 2024)	1 (May 14, 2024)	—	—

Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: project (parcel) · Retrieved Oct 26, 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.

Zoning & planning

Zoning: RS-20: Single Fam Res (min 20,000 SF) (Mill Valley)

Source: County of Marin GIS (MarinMap), Zoning (11 cities and unincorporated Marin) · Geography: zoning district polygon at parcel point · Retrieved Oct 31, 2026

Parcel facts

Lot size: 8,364 sq ft
Assessor land use: Single-Resid. - Improved
Addresses on parcel: 2

Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Oct 31, 2026

Official records

Assessor's property search
Search by parcel number 028-135-10. Assessed value is not market value.
Property tax bill
Search by parcel number 028-135-10 (Marin County Tax Collector)
County permit lookup
Permits issued in unincorporated Marin in the past 48 months. Each city keeps its own records.
FEMA Flood Map Service Center
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.

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

−$11,182/mo

-27.2%

$19,243/mo

−$11,228/mo

Base (your inputs)

Your entered assumptions, 3.0%/yr rent growth

$3,950/mo

−$10,729/mo

-26.1%

$17,811/mo

−$10,550/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

−$10,468/mo

-25.5%

$17,398/mo

−$10,035/mo

Report year

Project / record

Type

Entitled

Permitted

Completed

Deed-restricted

2024

JADU Convert Unconditioned(B-046603)

ADU · Renter

1 (Feb 15, 2024)

1 (May 14, 2024)

—