315 Tamalpais Ave

Mill Valley 94941 · APN 027-131-34 · 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 — within ½ mile: 6 homes completed, 1 permitted, 1 proposed or in review.

8 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.

No permit activity recorded within ½ mile.

Explore projects on the map →Explore sales & prices →

Estimated price, listing status & sales records

Benchmark valuation & transaction history

Estimated PriceArea benchmark

$2,422,000

Benchmark range: $2,059,000 – $2,785,000

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 (1.11×): Single-family lot (23,784 sq ft, +11.0% lot-size adjustment vs 6,000 sq ft standard lot); +$240,346
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 23,784 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 06041C0466F, 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

46 events · 19 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 (19)

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

StalledNew homeIssued
On this parcel
Permit issued and active for 9.2 yr (first record Aug 22, 2017), with no completion or new permit record in 9.2 yr. · 1 unit
StalledNew homeIssued
0.33 mi NE
Permit issued and active for 10.8 yr (first record Jan 12, 2016), with no completion or new permit record in 10.8 yr. · 1 unit
StalledNew homeIssued
0.5 mi SE
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
0.26 mi S
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 homeIssued
0.18 mi S
Permit issued and active for 8.8 yr (first record Jan 23, 2018), with no completion or new permit record in 8.8 yr. · 1 unit
StalledNew homeIssued
0.34 mi S
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

20261 event

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)

20257 events

Oct 21, 2025Nearby project · Entitled
0.45 mi SE
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 · Issued
0.48 mi E
SFR Tear Down — Issued
1 unit
Records span Oct 1, 2025 to Oct 13, 2025 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Oct 1, 2025Nearby project · Finaled / completed
0.18 mi W
New home — Finaled / completed
1 unit
Records span Feb 20, 2024 to Oct 1, 2025 (0 permits).
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)
Aug 21, 2025Nearby project · Finaled / completed
0.37 mi SE
Detached ADU — Finaled / completed
1 unit
Records span Jun 30, 2022 to Aug 21, 2025 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Aug 19, 2025Nearby project · Finaled / completed
0.42 mi SE
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
0.46 mi SE
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)

20247 events

Nov 19, 2024Nearby project · Finaled / completed
0.46 mi SE
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)
Oct 1, 2024Nearby project · Finaled / completed
0.36 mi E
Detached ADU — Finaled / completed
1 unit
Records span Jul 18, 2023 to Oct 1, 2024 (0 permits).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
September 2024Market trend
ZIP 94941
ZIP 94941 typical home value: $2,042,452 (+0.2% year-over-year)
Annual ZIP 94941 home-value index checkpoint
Changed from $2,038,275 in September 2023 to $2,042,452 in September 2024.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94941 (not a parcel appraisal)
Jun 4, 2024Nearby project · Entitled
0.13 mi S
Attached ADU — Entitled
1 unit
⏱ Slow turnaround:In "Entitled" for 2.4 yr (since Jun 4, 2024), with no new permit record in 2.4 yr.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Apr 16, 2024Nearby project · Issued
0.34 mi E
New home — Issued
1 unit
⏱ Slow turnaround:Permit issued and active for 2.5 yr (first record Apr 16, 2024), with no completion or new permit record in 2.5 yr.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Mar 28, 2024Nearby project · Issued
0.41 mi SE
Convert Unconditioned — Issued
1 unit
⏱ Slow turnaround:Permit issued and active for 2.6 yr (first record Mar 28, 2024), with no completion or new permit record in 2.6 yr.
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Feb 23, 2024Nearby project · Finaled / completed
0.44 mi N
New home — Finaled / completed
1 unit
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)

Showing 15 of 46 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

New homeIssuedNo new record in 9.2 yr
On this parcel
Active in "Issued" for 9.2 yr (first record Aug 22, 2017) with no new permit activity recorded in 9.2 yr.
Attached ADUEntitledNo new record in 2.4 yr
0.13 mi S
Active in "Entitled" for 2.4 yr (first record Jun 4, 2024) with no new permit activity recorded in 2.4 yr.
New homeIssuedNo new record in 8.8 yr
0.18 mi S
Active in "Issued" for 8.8 yr (first record Jan 23, 2018) with no new permit activity recorded in 8.8 yr.
New homeIssuedNo new record in 7.8 yr
0.22 mi S
Active in "Issued" for 7.8 yr (first record Jan 4, 2019) with no new permit activity recorded in 7.8 yr.
New homeIssuedNo new record in 9.1 yr
0.26 mi S
Active in "Issued" for 9.1 yr (first record Sep 15, 2017) with no new permit activity recorded in 9.1 yr.
New homeIssuedNo new record in 5.8 yr
0.3 mi W
Active in "Issued" for 5.8 yr (first record Jan 25, 2021) with no new permit activity recorded in 5.8 yr.

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 (%)$484,000Interest rate (%)Loan termClosing costs (%)$48,400

Prop 13 post-purchase property tax estimate

$2,357/mo ($28,280/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 ($24,200/yr) + local voter-approved bond debt ($3,630/yr) + fixed direct levies/Mello-Roos ($450/yr).

Voter bond rate (%)$3,630/yrDirect levies / Mello-Roos ($/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: −$11,811
Cash-on-cash return: -26.6%
Cap rate (Year 1 NOI): 0.21%
DSCR (NOI / debt): 0.03x
Break-even gross rent: $19,210/mo
Break-even vacancy: 0% (negative at full occ.)

Monthly cash-flow breakdown (Effective gross $3,753 − Operating $3,327 − Debt $12,237)

Gross scheduled rent$3,950

Vacancy allowance (5%)−$198

Effective gross income$3,753

Prop 13 property tax (1.17%)−$2,357

Property insurance−$275

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

Net Operating Income (NOI)+$426

Mortgage principal & interest (1,936,000 loan)−$12,237

Net monthly cash flow−$11,811

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	−$12,265/mo	-27.6%	$20,754/mo	−$12,325/mo
Base (your inputs)	Your entered assumptions, 3.0%/yr rent growth	$3,950/mo	−$11,811/mo	-26.6%	$19,210/mo	−$11,647/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	−$11,551/mo	-26.0%	$18,764/mo	−$11,132/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

New home
Issued1 unitsAug 22, 2017 – Aug 22, 2017

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
2018	B-036648(4494)	SFD · Owner	1 (Aug 22, 2017)	1 (Jun 13, 2018)	—	—
2018	B-036648(4494)	ADU · Renter	1 (Aug 22, 2017)	1 (Jun 13, 2018)	—	—

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: 23,784 sq ft
Assessor land use: Single-Resid. - Improved
Addresses on parcel: 1

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

Official records

Assessor's property search
Search by parcel number 027-131-34. Assessed value is not market value.
Property tax bill
Search by parcel number 027-131-34 (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

−$12,265/mo

-27.6%

$20,754/mo

−$12,325/mo

Base (your inputs)

Your entered assumptions, 3.0%/yr rent growth

$3,950/mo

−$11,811/mo

-26.6%

$19,210/mo

−$11,647/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

−$11,551/mo

-26.0%

$18,764/mo

−$11,132/mo

Report year

Project / record

Type

Entitled

Permitted

Completed

Deed-restricted

2018

B-036648(4494)

SFD · Owner

1 (Aug 22, 2017)

1 (Jun 13, 2018)

—

2018

B-036648(4494)

ADU · Renter

1 (Aug 22, 2017)

1 (Jun 13, 2018)

—