Mill Valley 94941 · Tamalpais · APN 050-101-10 · Unincorporated Marin
Zoned R1-B1 in Unincorporated Marin with likely ADU & SB 9 infill eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $2,056,000 ($1,809,000–$2,303,000).
Zoned R1-B1 supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 5,271 sq ft lot. Local precedent is active with 12 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 (5 total permits, latest Oct 4, 2021).
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. 16.3 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.
$2,056,000
Benchmark range: $1,809,000 – $2,303,000
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)
General repair (86492): Pending in review for 6.1 yr (27.0× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
Closest lead: New home at 217 Cleveland Ave (0.23 mi NE, 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 (~$2,008/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: 11 permitted, 12 proposed or in review; 2 demolitions; 1 commercial or mixed-use project.
26 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.
643 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 14, 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 14, 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 4.7 yr (first record Feb 14, 2022), with no completion or new permit record in 4.7 yr. · 1 unit · $33,896 declared valuation
In "Applied" for 4.5 yr (since Apr 27, 2022), with no new permit record in 4.5 yr. · 1 unit
Permit issued and active for 4.5 yr (first record May 4, 2022), with no completion or new permit record in 4.4 yr. · $8,000 declared valuation
Permit issued and active for 5.4 yr (first record Jun 21, 2021), with no completion or new permit record in 4.1 yr. · $15,000 declared valuation
Permit issued and active for 4 yr (first record Nov 29, 2022), with no completion or new permit record in 4 yr. · 1 unit · $33,550 declared valuation
In "Applied" for 3.9 yr (since Dec 23, 2022), with no new permit record in 3.9 yr. · $500,000 declared valuation
Nearby windows / doors / siding (188 Stanford Ave): First appeared in published agency feed
Record 94650 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (149 Morning Sun Ave): First appeared in published agency feed
Record 94645 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (4 Leo Ln): First appeared in published agency feed
Record B49100 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (403 Marin Ave): First appeared in published agency feed
Record B49090 · 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) (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 accessory dwelling unit (new or conversion) (3 Leo Ln (Aka 3 A)): First appeared in published agency feed
Record 182940 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby roof replacement (4 Leo Ln): First appeared in published agency feed
Record B49080 · 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 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 94306 · 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 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 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
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 →Pending in review for 6.1 yr (27.0× the 83d median) — slower than 90% of general repair permits in Unincorporated Marin (median 83d, 90th pct 328d, n=693).
Pending in review for 8.4 yr (18.8× the 164d median) — slower than 90% of new garage / accessory structure permits in Unincorporated Marin (median 164d, 90th pct 485d, n=356).
Active in "Issued" for 9.7 yr (first record Feb 21, 2017) with no new permit activity recorded in 2.3 yr. High-impact scale (1 housing unit, $875,000 declared valuation across 1 permit).
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 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 2.9 yr (first record Dec 21, 2023) with no new permit activity recorded in 19 mo. High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
Substantial improvements (additions, interior remodels, ADUs, commercial TI, and new builds) across 2,439 parcels
−7.7% YoY
City baseline: 16.3 / 1k
50 in trailing 24m
Includes 16 ADUs
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Merritt Nelson Bldrs | General repair | 1 on parcel1 in ½ mi | $27,000 | 0 vs 0 prior |
| Burkell Plumbing | HVAC / heat pump | 1 on parcel1 in ½ mi | $3,500 | 0 vs 0 prior |
| Owner Builder Recent nearby: 100 Loring Ave (Nov 10, 2026) | Remodel / interior alteration | 122 in ½ mi | $13,017,460 |
| Permit category | Sample (n) | 25th pct | Median (50th) | 75th pct | 90th pct | Recent 24m median |
|---|---|---|---|---|---|---|
| New single-family home | 121 | 166d | 253d | 456d | 686d | 210d(vs 276d prior) |
| New multifamily / condos / mixed-use | 21 | 272d | 292d | 293d | 313d | 293d(vs 197d prior) |
| New garage / accessory structureOn this parcel | 356 | 104d | 164d | 294d | 485d | 159d(vs 208d prior) |
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 ($20,550/yr) + local voter-approved bond debt ($3,083/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.
−$114,069/yr
Cash needed: $452,100
NOI: $10,625/yr
P&I: $10,391/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 | −$9,960/mo | -26.4% | $17,536/mo | −$9,979/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,950/mo | −$9,506/mo | -25.2% | $16,231/mo | −$9,302/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 | −$9,245/mo | -24.5% | $15,854/mo | −$8,786/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.
Interior Remodel - Master Bath; [N] Gas Compliant Fireplace
Retaining Wall
Water Proof Deck, Bring Hand Rails Up To Code, Patch Siding, Water Heater T.D. 9/4/19
New Roof, Struct Windows T.D. 7/17/18 10/11/18 Withdrawn
Replace HVAC and ducting under house with new wire flex and fittings — Replace Ductwork, Replace Mechanical Appliance
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel (APN) · Retrieved Nov 14, 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 14, 2026
0.12 acres
Assessor's classification for assessment purposes. This is not zoning.
322 SHEFFIELD AVE
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 14, 2026
Search by parcel number 050-101-10. Assessed value is not market value.
Search by parcel number 050-101-10 (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.
| 226 vs 240 prior−6% |
| Owner Recent nearby: 302 Starling Rd (Apr 10, 2025) | Remodel / interior alteration | 62 in ½ mi | $4,205,125 | 25 vs 15 prior+67% |
| International Building Investment Recent nearby: 396 Pine Hill Rd #37 (May 31, 2017) | Remodel / interior alteration | 12 in ½ mi | $173,200 | 0 vs 0 prior |
| Lamperti Contracting And Design Recent nearby: 370 Dolan Ave (Feb 15, 2024) | Remodel / interior alteration | 7 in ½ mi | $487,511 | 2 vs 7 prior |
| Leon Construction Recent nearby: 396 Pinehill Rd #10 (Sep 9, 2014) | Remodel / interior alteration | 7 in ½ mi | $224,000 | 0 vs 0 prior |
| Barton Design And Constuction Recent nearby: 406 Wendy Way (Oct 21, 2022) | Addition (adds square footage) | 6 in ½ mi | $1,525,000 | 0 vs 0 prior |
| Hunts Construction Partnership Recent nearby: 368 Shoreline Hwy (Aug 26, 2020) | Remodel / interior alteration | 6 in ½ mi | $495,000 | 0 vs 0 prior |
| Green Bay Remodeling Merged: GREEN BAY REMODELING · GREEN BAY REMODELING INC Recent nearby: 222 Julia Ave (Jun 9, 2025) | Remodel / interior alteration | 5 in ½ mi | $170,000 | 5 vs 5 prior |
| Accessory dwelling unit (new or conversion) | 298 | 120d | 204d | 331d | 549d | 214d(vs 181d prior) |
| Addition (adds square footage) | 316 | 103d | 160d | 249d | 440d | 159d(vs 166d prior) |
| Remodel / interior alterationOn this parcel | 1,054 | 36d | 83d | 148d | 266d | 112d(vs 77d prior) |
| Commercial tenant improvement | 81 | 99d | 148d | 233d | 443d | 152d(vs 150d prior) |
| 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.