Mill Valley 94941 · Almonte · APN 048-181-23 · Unincorporated Marin
Zoned R1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,166,000 ($1,906,000–$2,426,000).
Zoned R1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 8,799 sq ft lot. Local precedent is active with 3 ADU permits within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
Public building records show issued construction/renovation work on this parcel (6 total permits, latest Apr 21, 2023).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
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)
Automated synthesis of indexed municipal, county, state, and federal public records — informational context only, not a formal appraisal, survey, or legal/tax determination.
$2,166,000
Benchmark range: $1,906,000 – $2,426,000
Closest lead: 2 new homes (0.13 mi N, 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)
Sale triggers reassessment to 1.00% base + ~0.15% voter debt (~$2,113/mo). Confirm exact Mello-Roos / CFD special assessments on the county tax bill.
Source: CA Const. Art. XIIIA (Prop 13) · County Tax Collector
Since November 2024 within ½ mile: 1 homes completed, 6 permitted, 4 proposed or in review; 1 demolition; 1 commercial or mixed-use project.
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.
400 permits within ½ mile since November 2024
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.
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 Unincorporated Marin'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 R1 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.
In "Applied" for 6.9 yr (since Dec 24, 2019), with no new permit record in 6.9 yr. · 1 unit · $600,000 declared valuation
Permit issued and active for 6.7 yr (first record Feb 20, 2020), with no completion or new permit record in 6.7 yr. · 1 unit · $125,000 declared valuation
In "Applied" for 6.5 yr (since May 29, 2020), with no new permit record in 6.5 yr. · $5,000 declared valuation
In "Applied" for 6.4 yr (since Jun 25, 2020), with no new permit record in 6.4 yr. · 1 unit · $15,500 declared valuation
In "Entitled" for 6.2 yr (since Sep 9, 2020), with no new permit record in 6.2 yr. · 1 unit
Permit issued and active for 6.2 yr (first record Sep 14, 2020), with no completion or new permit record in 6.2 yr. · 1 unit
Nearby accessory dwelling unit (new or conversion) (100 Loring Ave): First appeared in published agency feed
Record 182935 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby general repair (100 Loring Ave): First appeared in published agency feed
Record 182934 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby general repair (100 Loring Ave): No longer present in latest agency feed
Record 94068 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Record 93891 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (250 Loring Ave): First appeared in published agency feed
Record B48929 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby plumbing / water heater / sewer (63 California Ave): First appeared in published agency feed
Record B49068 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (908 Vernal Way): First appeared in published agency feed
Record B49065 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (910 W California Ave): First appeared in published agency feed
Record B49064 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (141 Morning Sun Ave): Description text was updated
Record B48902 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby roof replacement (905 Greenhill Rd): First appeared in published agency feed
Record B48983 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (201 Hawthorne Ave): Description text was updated
Record B48724 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby plumbing / water heater / sewer (211 Cleveland Ave): First appeared in published agency feed
Record B48909 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (141 Morning Sun Ave): First appeared in published agency feed
Record B48902 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
123 Morning Sun Ave · $20,000 valuation
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project 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)
Cross-referenced intelligence from our historical development graph—connecting parcels, permits, entity-resolved builders, empirical review-time distributions, and neighborhood renovation trends.
Explore full Unincorporated Marin development graph →Active in "Issued" for 5.7 yr (first record Mar 1, 2021) with no new permit activity recorded in 5.7 yr. High-impact scale (2 housing units, 1 deed-restricted affordable across 0 permits).
Active in "Issued" for 5.7 yr (first record Mar 1, 2021) with no new permit activity recorded in 5.7 yr. High-impact scale (2 housing units, 1 deed-restricted affordable across 0 permits).
Active in "Issued" for 23 mo (first record Dec 26, 2024) with no new permit activity recorded in 18 mo. High-impact scale ($6,500,000 declared valuation across 1 permit).
Active in "Issued" for 5.4 yr (first record Jun 9, 2021) with no new permit activity recorded in 5.4 yr. High-impact scale (9 housing units across 0 permits).
Active in "Issued" for 4.8 yr (first record Jan 19, 2022) with no new permit activity recorded in 3.4 yr. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
Active in "Issued" for 3.1 yr (first record Oct 12, 2023) with no new permit activity recorded in 2.6 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
Substantial improvements (additions, interior remodels, ADUs, commercial TI, and new builds) across 738 parcels
Small prior baseline
City baseline: 16.4 / 1k
12 in trailing 24m
Includes 1 ADUs
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Sun First | Solar / battery storage | 2 on parcel2 in ½ mi | $51,500 | 0 vs 0 prior |
| Ernest Ongaro And Sons | Electrical / panel | 2 on parcel2 in ½ mi | $13,900 | 0 vs 0 prior |
| Massa Construction | General repair | 1 on parcel1 in ½ mi | $40,000 | 0 |
| Permit category | Sample (n) | 25th pct | Median (50th) | 75th pct | 90th pct | Recent 24m median |
|---|---|---|---|---|---|---|
| New single-family home | 121 | 166d | 253d | 456d | 686d | 211d(vs 273d prior) |
| New multifamily / condos / mixed-use | 21 | 272d | 292d | 293d | 313d | 293d(vs 197d prior) |
| Accessory dwelling unit (new or conversion) | 298 | 120d | 204d | 331d | 549d | 214d(vs 181d prior) |
| Addition (adds square footage) |
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 ($21,650/yr) + local voter-approved bond debt ($3,248/yr) + fixed direct levies/Mello-Roos ($450/yr).
Insurance & hazard context:
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.
−$122,009/yr
Cash needed: $476,300
NOI: $9,360/yr
P&I: $10,947/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 | −$10,621/mo | -26.8% | $18,460/mo | −$10,650/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,950/mo | −$10,167/mo | -25.6% | $17,086/mo | −$9,972/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 | −$9,907/mo | -25.0% | $16,689/mo | −$9,456/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.
SCOPE 4.000 kW DC ROOF MOUNT SOLAR PV SYSTEM, 10 PANASONIC 400W EVPV400H PV MODULES, 1 SOLAREDGE SE11400H-US INVERTERS. GENERAL NOTES 1. 20° ROOF PITCH 2. 2 X 4 DF TRUSS @ 24 O.C. 3. ROLLED COMP ROOF 4. (10) PANASONIC 400W PV MODULES 5. (1) SOLAREDGE SE11400H-US INVERTER(S) 6. SNAP N RACK SERIES 100 RAIL 7. SNAP N RACK BONDING CLAMPS, L FEET AND CHANNEL NUTES FOR PV GROUNDING
Replace furnace with new Air Handler and install Heat Pump - new — Mechanical Appliance, Replace Mechanical Appliance
Replace 100 amp main panel with 200 amp solar ready main panel. The new panel will be surface mounted in the same location as the existing. No added loads. — Service Upgrade
Energy Storage System
New Retaining Walls Below House
6.9kw Roof Mount Photovoltaic - Express
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.
No housing activity reported to the State for this parcel (2018–2025 reports).
Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: project (parcel) · Retrieved Nov 9, 2026 · From Unincorporated Marin'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
0.20 acres
Assessor's classification for assessment purposes. This is not zoning.
3 MAXWELL LN
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 048-181-23. Assessed value is not market value.
Search by parcel number 048-181-23 (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.
| Firstpv | Solar / battery storage | 1 on parcel1 in ½ mi | $17,850 | 0 vs 0 prior |
| Owner Builder Recent nearby: 100 Loring Ave (Nov 10, 2026) | Remodel / interior alteration | 85 in ½ mi | $9,242,587 | 226 vs 240 prior−6% |
| Owner Recent nearby: 164 Morning Sun Ave (Mar 2, 2022) | Remodel / interior alteration | 35 in ½ mi | $1,757,000 | 25 vs 15 prior+67% |
| Juan Calmell Recent nearby: 167 Lavender Ln (And 169) (Sep 16, 2015) | Remodel / interior alteration | 5 in ½ mi | $110,450 | 0 vs 0 prior |
| Spellbound Construction Recent nearby: 124 Reed St (Oct 30, 2014) | Addition (adds square footage) | 4 in ½ mi | $873,000 | 2 vs 1 prior |
| Tamalpais Construction Recent nearby: 20 Morning Sun Ave (Nov 3, 2022) | Remodel / interior alteration | 4 in ½ mi | $193,000 | 0 vs 2 prior |
| Miette Recent nearby: 210 California Ave (Jul 23, 2020) | Demolition | 3 in ½ mi | $853,000 | 0 vs 0 prior |
| 316 |
| 103d |
| 160d |
| 249d |
| 440d |
| 157d(vs 167d prior) |
| Remodel / interior alteration | 1,054 | 36d | 83d | 148d | 266d | 112d(vs 77d prior) |
| Commercial tenant improvement | 81 | 99d | 148d | 233d | 443d | 152d(vs 150d prior) |
| Solar / battery storageOn this parcel | 2,977 | 0d | 0d | 0d | 2d | 0d |
| HVAC / heat pumpOn this parcel | 2,946 | 0d | 0d | 0d | 0d | 0d |
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Computed from issued permits with recorded application and issuance dates over the trailing 60 months. Categories with fewer than 20 permits are excluded.