San Quentin 94964 · San Quentin · APN 018-163-31 · Unincorporated Marin
Zoned RMP-11.7 in Unincorporated Marin with likely ministerial ADU eligibility and zero mapped flood, fire, or fault hazard overlaps; benchmark value $1,498,000 ($1,273,000–$1,723,000).
Zone RMP-11.7 allows residential use qualifying for ministerial ADU review under state law.
Source: Unincorporated Marin zoning · CA Gov. Code 66314
Public building records show issued construction/renovation work on this parcel (12 total permits, latest Oct 28, 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.
12 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
$1,498,000
Benchmark range: $1,273,000 – $1,723,000
Remodel / interior alteration (173802): Issued after 22 mo (8.0× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (review-time benchmark)
Closest lead: New home at 22 Mckenzie St (340 ft W, 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 (~$1,473/mo). Confirm exact Mello-Roos / CFD special assessments on the county tax bill.
Source: CA Const. Art. XIIIA (Prop 13) · County Tax Collector
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 RMP-11.7 as multifamily 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 3.9 yr (first record Dec 27, 2022), with no completion or new permit record in 2.8 yr. · 1 unit · $850,000 declared valuation
Nearby remodel / interior alteration (130 Le Cante Dr): Contractor changed from (blank) to BOLT DOWN THE BAY AREA
Record 182711 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
22 Mckenzie St · 1 unit · $850,000 valuation
Records span Dec 27, 2022 to Jan 22, 2024 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Electrical / panel permit application filed (B35933)
Current status: Issued
Like for like replacement of electric panels for Units 18 and 20. — Replace Circuits / Outlets · Declared valuation: $2,000 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Electrical / panel permit issued (B35933)
Recorded status: Issued
Like for like replacement of electric panels for Units 18 and 20. — Replace Circuits / Outlets · Declared valuation: $2,000 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Remodel / interior alteration permit issued (173802)
Recorded status: Issued
Remodel Apartment - Express **Application Extended To 8/11/23; Nh/Bbw · Declared valuation: $75,000 · Contractor: Owner/Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
38 Main St (Aka 38a) · 1 unit · $225,000 valuation
Records span Aug 29, 2022 to Apr 10, 2023 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
EV charger permit issued (B31672)
Recorded status: Issued
EV charging dual ports — EV Charging Station · Declared valuation: $5,000 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
EV charger permit application filed (B31672)
Current status: Issued
EV charging dual ports — EV Charging Station · Declared valuation: $5,000 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Remodel / interior alteration permit application filed (173802)
Current status: Issued
Remodel Apartment - Express **Application Extended To 8/11/23; Nh/Bbw · Declared valuation: $75,000 · Contractor: Owner/Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
New garage / accessory structure permit issued (157066)
Recorded status: Issued
ew Laundry Room (Detached) (Includes Separage Electrical And Gas Meter) T.D. 3/20/17. · Declared valuation: $36,000 · Contractor: James Flanagan Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Roof replacement permit application filed (B12764)
Current status: Issued
Reroof, replace gutters and flashing as needed — ReRoofing · Declared valuation: $15,980 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Roof replacement permit issued (B12764)
Recorded status: Issued
Reroof, replace gutters and flashing as needed — ReRoofing · Declared valuation: $15,980 · Contractor: Owner
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Remodel / interior alteration permit issued (155519)
Recorded status: Issued
Remod Apartment. T.D. 3/20/17. Submitted 4/21/17. Scb. . Re-Submitted 5/2/17. Re-Reviewed And Out For Corrections 5/11. Scb. · Declared valuation: $20,000 · Contractor: James Flanagan Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Remodel / interior alteration permit application filed (155519)
Current status: Issued
Remod Apartment. T.D. 3/20/17. Submitted 4/21/17. Scb. . Re-Submitted 5/2/17. Re-Reviewed And Out For Corrections 5/11. Scb. · Declared valuation: $20,000 · Contractor: James Flanagan Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
New garage / accessory structure permit application filed (157066)
Current status: Issued
ew Laundry Room (Detached) (Includes Separage Electrical And Gas Meter) T.D. 3/20/17. · Declared valuation: $36,000 · Contractor: James Flanagan Builder
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
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 →Issued after 22 mo (8.0× the 83d median) — slower than 90% of remodel / interior alteration permits in Unincorporated Marin (median 83d, 90th pct 266d, n=1,054).
Active in "Issued" for 3.9 yr (first record Dec 27, 2022) with no new permit activity recorded in 2.8 yr. High-impact scale (1 housing unit, $850,000 declared valuation across 1 permit).
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Owner | Electrical / panel | 7 on parcel7 in ½ mi | $37,980 | 25 vs 15 prior+67% |
| James Flanagan Builder | New garage / accessory structure | 2 on parcel2 in ½ mi | $56,000 | 0 vs 1 prior |
| Owner Builder | Remodel / interior alteration | 1 on parcel1 in ½ mi | $75,000 |
| 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 94964
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 ($18,235/yr) + local voter-approved bond debt ($2,735/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.
Statutory notes: Under CA Gov. Code § 66324 (SB 13), local agencies cannot impose development impact fees on ADUs under 750 sq ft (plan-check, school district fees ≥500 sq ft, and utility connection fees still apply). Under CA Rev. & Tax. Code § 71, building an ADU triggers a supplemental assessment on the new construction value without reassessing the existing dwelling or land. Newly built ADUs also carry a rolling 15-year exemption from statewide AB 1482 rent caps from certificate of occupancy.
−$75,508/yr
Cash needed: $410,875
NOI: $38,522/yr
P&I: $9,502/mo
For $0/mo net cash flow
At $6,725/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 | $6,187/mo | −$7,065/mo | -20.6% | $16,049/mo | −$6,954/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $6,725/mo | −$6,292/mo | -18.4% | $14,855/mo | −$5,800/mo |
| Optimistic (cap-limited) | +6% starting rent, 3% vacancy, 4.5%/yr rent growth (capped by AB 1482 ceiling of 8.6%/yr) | $7,129/mo | −$5,848/mo | -17.1% | $14,510/mo | −$4,922/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.
Like for like replacement of electric panels for Units 18 and 20. — Replace Circuits / Outlets
Remodel Apartment - Express **Application Extended To 8/11/23; Nh/Bbw
EV charging dual ports — EV Charging Station
ew Laundry Room (Detached) (Includes Separage Electrical And Gas Meter) T.D. 3/20/17.
Reroof, replace gutters and flashing as needed — ReRoofing
Remod Apartment. T.D. 3/20/17. Submitted 4/21/17. Scb. . Re-Submitted 5/2/17. Re-Reviewed And Out For Corrections 5/11. Scb.
REROOF DUPLEX — ReRoofing
Upgr Main Service
Repair Main Panel Box
Rmdl Kit & Ba, Baseboard Heater & Lighting In Other Areas
Elect, Mech & Plbg In Kitch Of Unit 18, Baseboard Htr In 18; Fan In Bath Of 18; Rpr Crct Box In 24.Prmt Superceded By Permit # Refund Prep. 11/17/1
Repl & Reconfig Front Porch, Cov For Upper Deck & Roof Ext; Siding, Add & Subtract Wndws***Ext To 7/20/18 *Roof Ext. Deleted Per Owner.
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
0.26 acres
Assessor's classification for assessment purposes. This is not zoning.
18 MAIN ST; 18 MAIN ST A; 20 MAIN ST
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 14, 2026
Search by parcel number 018-163-31. Assessed value is not market value.
Search by parcel number 018-163-31 (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% |
| Flanagan James Builder | New garage / accessory structure | 1 on parcel1 in ½ mi | $44,000 | 0 vs 0 prior |
| Ja Roofing | Roof replacement | 1 on parcel1 in ½ mi | $10,500 | 0 vs 0 prior |
| Rodd Renovations Recent nearby: 22 Mckenzie St (Jan 22, 2024) | New single-family home | 1 in ½ mi | $850,000 | 0 vs 0 prior |
| Bolt Down The Bay Area Recent nearby: 130 Le Cante Dr (Oct 12, 2026) | Remodel / interior alteration | 1 in ½ mi | $287,000 | 5 vs 0 prior |
| Kearney Construction Recent nearby: 38 Main St (Aka 38a) (Apr 10, 2023) | Accessory dwelling unit (new or conversion) | 1 in ½ mi | $225,000 | 2 vs 3 prior |
| Guthrie Construction Recent nearby: 80 Heron Ct (Mar 7, 2024) | Remodel / interior alteration | 1 in ½ mi | $196,000 | 0 vs 3 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) |
| EV chargerOn this parcel | 482 | 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.