Stinson Beach 94970 · Stinson Beach · APN 195-340-25 · Unincorporated Marin
Zoned C-RSPS-1.4 in Unincorporated Marin with likely ministerial ADU eligibility and mapped FEMA A flood due diligence; benchmark value $3,022,000 ($2,659,000–$3,385,000).
Zone C-RSPS-1.4 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 (4 total permits, latest Jun 24, 2026).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
Zone A: 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)
Automated synthesis of indexed municipal, county, state, and federal public records — informational context only, not a formal appraisal, survey, or legal/tax determination.
Since November 2024 within ½ mile: 3 permitted.
3 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.
58 permits within ½ mile since November 2024
$3,022,000
Benchmark range: $2,659,000 – $3,385,000
Closest lead: New home at 252 Seadrift Rd (360 ft SE, 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 (~$2,934/mo). Confirm exact Mello-Roos / CFD special assessments on the county tax bill.
Source: CA Const. Art. XIIIA (Prop 13) · County Tax Collector
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 C-RSPS-1.4 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 12.8 yr (first record Jan 16, 2014), with no completion or new permit record in 12.3 yr. · 1 unit · $1,452,000 declared valuation
Permit issued and active for 12.6 yr (first record Apr 10, 2014), with no completion or new permit record in 12.2 yr. · 1 unit · $400,000 declared valuation
Permit issued and active for 12.9 yr (first record Dec 23, 2013), with no completion or new permit record in 12.2 yr. · 1 unit · $445,000 declared valuation
Permit issued and active for 11.7 yr (first record Mar 10, 2015), with no completion or new permit record in 11.3 yr. · $681,143 declared valuation
Permit issued and active for 9.6 yr (first record Apr 19, 2017), with no completion or new permit record in 9.5 yr. · 1 unit · $450,000 declared valuation
Permit issued and active for 10.7 yr (first record Mar 8, 2016), with no completion or new permit record in 9.5 yr. · 1 unit · $550,000 declared valuation
Nearby other (206 Seadrift Rd): First appeared in published agency feed
Record B49006 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (279 Seadrift Rd): First appeared in published agency feed
Record B48962 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Latest published Zillow Home Value Index (ZHVI) update
Changed from $3,185,829 in September 2025 to $3,577,374 in September 2026.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94970 (not a parcel appraisal)
Plumbing / water heater / sewer permit application filed (B47275)
Current status: Issued
Replace Plumbing Fixtures(s) · Declared valuation: $21,454 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Plumbing / water heater / sewer permit issued (B47275)
Recorded status: Issued
Replace Plumbing Fixtures(s) · Declared valuation: $21,454 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
229 Seadrift Rd · 1 unit · $1,200,000 valuation
Records span Jul 21, 2025 to Jan 7, 2026 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Annual ZIP 94970 home-value index checkpoint
Changed from $3,436,866 in September 2024 to $3,185,829 in September 2025.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94970 (not a parcel appraisal)
HVAC / heat pump permit application filed (B42977)
Current status: Issued
Installation of 5 Ton Mitsubishi Mini Split System on left side yard — Mechanical Appliance · Declared valuation: $23,877 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
HVAC / heat pump permit issued (B42977)
Recorded status: Issued
Installation of 5 Ton Mitsubishi Mini Split System on left side yard — Mechanical Appliance · Declared valuation: $23,877 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
227 Seadrift Rd · 1 unit
Records span Dec 27, 2024 to May 19, 2025 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Solar / battery storage permit application filed (B42410)
Current status: Issued
Rooftop 14 panel solar system with 2 batteries and 200A System controller · Declared valuation: $23,922 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Solar / battery storage permit issued (B42410)
Recorded status: Issued
Rooftop 14 panel solar system with 2 batteries and 200A System controller · Declared valuation: $23,922 · Contractor: Ernest Ongaro & Sons Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Solar / battery storage permit application filed (B40544)
Current status: Issued
SYSTEM SIZE: 6.150kW DC / 5.966kW AC SYSTEM SIZE PV MODULE: (15) HANWHA Q.PEAK DUO BLK ML-G10+415 INVERTER: (15) ENPHASE IQ8PLUS-72-M-US COMBINER: (1) 125A ENPHASE X-IQ-AM1-240-5/5C AC DISCONNECT: (1) 100A UNFUSED AC DISCONNECT BATTERY: (3) ENPHASE IQ 5P · Declared valuation: $5,000 · Contractor: Solarsesame Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
Solar / battery storage permit issued (B40544)
Recorded status: Issued
SYSTEM SIZE: 6.150kW DC / 5.966kW AC SYSTEM SIZE PV MODULE: (15) HANWHA Q.PEAK DUO BLK ML-G10+415 INVERTER: (15) ENPHASE IQ8PLUS-72-M-US COMBINER: (1) 125A ENPHASE X-IQ-AM1-240-5/5C AC DISCONNECT: (1) 100A UNFUSED AC DISCONNECT BATTERY: (3) ENPHASE IQ 5P · Declared valuation: $5,000 · Contractor: Solarsesame Inc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
1 unit
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 9.2 yr (first record Sep 5, 2017) with no new permit activity recorded in 8.9 yr. High-impact scale (1 housing unit, $1,600,000 declared valuation across 1 permit).
Active in "Issued" for 12.8 yr (first record Jan 16, 2014) with no new permit activity recorded in 12.3 yr. High-impact scale (1 housing unit, $1,452,000 declared valuation across 1 permit).
Active in "Issued" for 9.4 yr (first record Jun 12, 2017) with no new permit activity recorded in 9 yr. High-impact scale (1 housing unit, $900,000 declared valuation across 1 permit).
Active in "Issued" for 6.9 yr (first record Dec 30, 2019) with no new permit activity recorded in 4.4 yr. High-impact scale (1 housing unit, $2,500,000 declared valuation across 1 permit).
Active in "Issued" for 9.4 yr (first record Jun 19, 2017) with no new permit activity recorded in 9.3 yr. High-impact scale (1 housing unit, $1,485,000 declared valuation across 1 permit).
Active in "Issued" for 3.7 yr (first record Mar 13, 2023) with no new permit activity recorded in 2.8 yr. High-impact scale (1 housing unit, $960,000 declared valuation across 1 permit).
Substantial improvements (additions, interior remodels, ADUs, commercial TI, and new builds) across 891 parcels
Small prior baseline
City baseline: 16.4 / 1k
9 in trailing 24m
Includes 2 ADUs
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Ernest Ongaro And Sons | HVAC / heat pump | 3 on parcel3 in ½ mi | $69,253 | 0 vs 0 prior |
| Solarsesame | Solar / battery storage | 1 on parcel1 in ½ mi | $5,000 | 0 vs 0 prior |
| Gubbins Building Recent nearby: 227 Seadrift Rd (May 19, 2025) | Remodel / interior alteration | 15 in ½ mi | $8,049,500 |
| 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 94970
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 ($30,200/yr) + local voter-approved bond debt ($4,530/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.
−$193,633/yr
Cash needed: $664,400
NOI: -$10,384/yr
P&I: $15,271/mo
For $0/mo net cash flow
At $3,025/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 | $2,783/mo | −$16,484/mo | -29.8% | $25,792/mo | −$16,628/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,025/mo | −$16,136/mo | -29.1% | $23,873/mo | −$16,109/mo |
| Optimistic (cap-limited) | +6% starting rent, 3% vacancy, 4.5%/yr rent growth (capped by AB 1482 ceiling of 8.6%/yr) | $3,207/mo | −$15,936/mo | -28.8% | $23,318/mo | −$15,714/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.
Replace Plumbing Fixtures(s)
Installation of 5 Ton Mitsubishi Mini Split System on left side yard — Mechanical Appliance
Rooftop 14 panel solar system with 2 batteries and 200A System controller
SYSTEM SIZE: 6.150kW DC / 5.966kW AC SYSTEM SIZE PV MODULE: (15) HANWHA Q.PEAK DUO BLK ML-G10+415 INVERTER: (15) ENPHASE IQ8PLUS-72-M-US COMBINER: (1) 125A ENPHASE X-IQ-AM1-240-5/5C AC DISCONNECT: (1) 100A UNFUSED AC DISCONNECT BATTERY: (3) ENPHASE IQ 5P
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
0.17 acres
Assessor's classification for assessment purposes. This is not zoning.
257 SEADRIFT RD
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 195-340-25. Assessed value is not market value.
Search by parcel number 195-340-25 (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.
| 3 vs 4 prior |
| Peterson Construction And Development Recent nearby: 121 Dipsea Rd (Nov 18, 2020) | New single-family home | 10 in ½ mi | $8,524,356 | 0 vs 4 prior |
| Kasten Builders Recent nearby: 340 Seadrift Rd (May 23, 2023) | New single-family home | 9 in ½ mi | $5,853,140 | 2 vs 5 prior |
| Allen Construction Recent nearby: 168 Seadrift Rd (May 6, 2022) | New single-family home | 9 in ½ mi | $4,367,078 | 0 vs 0 prior |
| Schalich Brothers Construction Recent nearby: 117 Dipsea Rd (Apr 1, 2025) | New single-family home | 5 in ½ mi | $7,552,000 | 7 vs 1 prior |
| Matarozzi Pelsinger Builders Recent nearby: 238 Seadrift Rd (Jul 9, 2021) | New single-family home | 4 in ½ mi | $6,600,000 | 1 vs 2 prior |
| Owner Recent nearby: 288 Seadrift Rd (Oct 15, 2020) | Remodel / interior alteration | 4 in ½ mi | $2,095,000 | 25 vs 15 prior+67% |
| Apache Pools Recent nearby: 218 Seadrift Rd (May 20, 2022) | Pool / spa | 4 in ½ mi | $270,000 | 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.