Mill Valley 94941 · Tamalpais · APN 052-042-70 · Unincorporated Marin
Zoned R1-B1 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA AE flood / CAL FIRE moderate fire hazard severity zone (local responsibility area) due diligence; benchmark value $2,140,000 ($1,883,000–$2,397,000).
Zone R1-B1 allows residential use qualifying for ministerial ADU review under state law (2 ADU permits permitted within ¼ mile in 36 months).
Source: Unincorporated Marin zoning · CA Gov. Code 66314
On-parcel permit history is indexed through Nov 17, 2020, 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)
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)
Automated synthesis of indexed municipal, county, state, and federal public records — informational context only, not a formal appraisal, survey, or legal/tax determination.
$2,140,000
Benchmark range: $1,883,000 – $2,397,000
Zone AE: 1% annual chance flood (Special Flood Hazard Area) overlaps this parcel. Expect mandatory flood insurance for federally backed loans and floodplain elevation/mitigation rules for new units or SB 9 applications.
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)
Closest lead: New commercial building at 201 Flamingo Rd (aka 205) (0.22 mi NW, 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 (~$2,088/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: 6 permitted, 8 proposed or in review; 1 demolition.
16 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.
482 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-B1 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 13 yr (first record Oct 28, 2013), with no completion or new permit record in 12.1 yr. · 1 unit · $600,000 declared valuation
Permit issued and active for 11.7 yr (first record Feb 17, 2015), with no completion or new permit record in 11.2 yr. · $3,938,400 declared valuation
Permit issued and active for 10.5 yr (first record May 24, 2016), with no completion or new permit record in 10.3 yr. · $10,000 declared valuation
Permit issued and active for 11.9 yr (first record Dec 23, 2014), with no completion or new permit record in 10 yr. · 1 unit · $900,000 declared valuation
In "Applied" for 9.6 yr (since Mar 20, 2017), with no new permit record in 9.6 yr. · $250,000 declared valuation
Permit issued and active for 9.6 yr (first record Mar 28, 2017), with no completion or new permit record in 9.6 yr. · $250 declared valuation
Nearby remodel / interior alteration (303 Dawn Ct): Description text was updated
Record 94638 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby roof replacement (250 Morning Sun Ave): First appeared in published agency feed
Record B49077 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby remodel / interior alteration (303 Dawn Ct): First appeared in published agency feed
Record 94638 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (358 Starling Rd): First appeared in published agency feed
Record B49046 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby plumbing / water heater / sewer (400 Tennessee Glen Way): First appeared in published agency feed
Record B49038 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby roof replacement (330 Tennessee Ave): First appeared in published agency feed
Record B49023 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (301 Tennessee Valley Rd): First appeared in published agency feed
Record B49005 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby accessory dwelling unit (new or conversion) (254 Cleveland Ave): First appeared in published agency feed
Record 94629 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Record 94571 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Record 94571 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (240 Perry St): First appeared in published agency feed
Record B48926 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (254 Shoreline Hwy): First appeared in published agency feed
Record B48920 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby windows / doors / siding (220 Cardinal Rd): First appeared in published agency feed
Record B48903 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (354 Starling Rd): First appeared in published agency feed
Record B48885 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
310 Tennessee Ave · 1 unit · $250,000 valuation
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 Unincorporated Marin development graph →Active in "Issued" for 11.7 yr (first record Feb 17, 2015) with no new permit activity recorded in 11.2 yr. High-impact scale ($3,938,400 declared valuation across 3 permits).
Active in "Issued" for 8.2 yr (first record Sep 5, 2018) with no new permit activity recorded in 8 yr. High-impact scale (1 housing unit, $759,000 declared valuation across 1 permit).
Active in "Issued" for 6 yr (first record Oct 29, 2020) with no new permit activity recorded in 4 yr. High-impact scale (1 housing unit, $800,000 declared valuation across 1 permit).
Active in "Issued" for 11.9 yr (first record Dec 23, 2014) with no new permit activity recorded in 10 yr. High-impact scale (1 housing unit, $900,000 declared valuation across 1 permit).
In "Applied" for 2 yr (since Nov 21, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
In "Applied" for 2 yr (since Oct 31, 2024), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121).
Substantial improvements (additions, interior remodels, ADUs, commercial TI, and new builds) across 2,439 parcels
−7.7% YoY
City baseline: 16.4 / 1k
50 in trailing 24m
Includes 16 ADUs
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Home Depot USA | Windows / doors / siding | 1 on parcel1 in ½ mi | $3,393 | 0 vs 0 prior |
| Glad Electric Service | Electrical / panel | 1 on parcel1 in ½ mi | $3,000 | 0 vs 0 prior |
| Harris Water Heaters | Plumbing / water heater / sewer | 1 on parcel1 in ½ mi | $1,837 | 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 ($21,400/yr) + local voter-approved bond debt ($3,210/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.
−$121,524/yr
Cash needed: $470,800
NOI: $8,328/yr
P&I: $10,821/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 | −$10,581/mo | -27.0% | $18,404/mo | −$10,619/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,950/mo | −$10,127/mo | -25.8% | $17,034/mo | −$9,941/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 | −$9,867/mo | -25.1% | $16,638/mo | −$9,425/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.
Install 50 gallon water heater, like for like, in garage — Replace Plumbing Fixtures(s)
service upgrade for car charging and panel relocation. — Service Upgrade
REPLACE 4 WINDOWS IN KIND — Non-structural Door/Window Replacement
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
0.21 acres
Assessor's classification for assessment purposes. This is not zoning.
252 CARDINAL RD
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 052-042-70. Assessed value is not market value.
Search by parcel number 052-042-70 (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.
| Owner Builder Recent nearby: 312 Dolan Ave (Oct 16, 2026) | Remodel / interior alteration | 51 in ½ mi | $7,223,716 | 226 vs 240 prior−6% |
| Owner Recent nearby: 302 Starling Rd (Apr 10, 2025) | Remodel / interior alteration | 35 in ½ mi | $2,561,125 | 25 vs 15 prior+67% |
| Ga Higgins Recent nearby: 487 Sherwood Dr - Apt #304 (Mar 24, 2017) | Remodel / interior alteration | 22 in ½ mi | $235,600 | 0 vs 0 prior |
| Rods General Builders Recent nearby: 427 Sherwood Dr - Apt #306 (Mar 24, 2017) | Remodel / interior alteration | 13 in ½ mi | $136,700 | 0 vs 0 prior |
| Lek Enterprises Recent nearby: 214 Villa Garden Dr Units Bldg 214 A-D (May 1, 2019) | Remodel / interior alteration | 6 in ½ mi | $127,400 | 0 vs 11 prior−100% |
| Chesapeake Finishing Recent nearby: 439 Sherwood Dr (Aug 3, 2017) | New garage / accessory structure | 5 in ½ mi | $440,000 | 0 vs 0 prior |
| Lamperti Contracting And Design Recent nearby: 370 Dolan Ave (Feb 15, 2024) | Remodel / interior alteration | 4 in ½ mi | $321,261 | 2 vs 7 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) |
| Electrical / panelOn this parcel | 3,019 | 0d | 0d | 0d | 2d | 0d |
| Plumbing / water heater / sewerOn this parcel | 2,211 | 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.