San Anselmo 94960 · Sleepy Hollow · APN 177-051-09 · Unincorporated Marin
Zoned R1-BD in Unincorporated Marin with likely ADU & SB 9 infill eligibility and mapped CAL FIRE moderate fire hazard severity zone (state responsibility area) due diligence; benchmark value $1,980,000 ($1,742,000–$2,218,000).
Zoned R1-BD supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 17,947 sq ft lot. Local precedent is active with 2 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 Apr 26, 2024).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (parcel APN)
32 substantial renovation & housing permits over 24 months (32.7 per 1,000 parcels vs. 16.4 citywide baseline) (#4 of 22 neighborhoods).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) (Sleepy Hollow)
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: 2 permitted, 1 proposed or in review.
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.
184 permits within ½ mile since November 2024
$1,980,000
Benchmark range: $1,742,000 – $2,218,000
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)
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 Apr 1, 2024)
Closest lead: New home at 666 Fawn Dr (0.44 mi E, applied). 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 (~$1,935/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 R1-BD 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 12.9 yr (first record Dec 24, 2013), with no completion or new permit record in 12.4 yr. · 1 unit · $800,000 declared valuation
Permit issued and active for 10.2 yr (first record Aug 23, 2016), with no completion or new permit record in 10.1 yr. · $10,000 declared valuation
Permit issued and active for 8.7 yr (first record Feb 14, 2018), with no completion or new permit record in 8.7 yr. · 1 unit
Permit issued and active for 8.3 yr (first record Aug 9, 2018), with no completion or new permit record in 7.6 yr. · 1 unit · $1,097,000 declared valuation
In "Applied" for 7.5 yr (since Apr 29, 2019), with no new permit record in 7.5 yr. · 1 unit · $1,000,000 declared valuation
Permit issued and active for 7.7 yr (first record Feb 21, 2019), with no completion or new permit record in 7.5 yr. · 1 unit · $35,000 declared valuation
Nearby other (7 Quail Way): First appeared in published agency feed
Record B49094 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby roof replacement (150 W Oak Knoll Dr): First appeared in published agency feed
Record B49088 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby plumbing / water heater / sewer (980 Butterfield Rd): First appeared in published agency feed
Record B49066 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby pool / spa (111 Deer Hollow Rd): First appeared in published agency feed
Record 94635 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (635 Fawn Dr): First appeared in published agency feed
Record B49033 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby hvac / heat pump (230 Deer Hollow Rd): First appeared in published agency feed
Record B48980 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (2 Michael Way): First appeared in published agency feed
Record B48977 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby general repair (200 Deer Hollow Rd): Description text was updated
Record 94619 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby ev charger (50 Van Hooten Ct): First appeared in published agency feed
Record B48946 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby general repair (200 Deer Hollow Rd): First appeared in published agency feed
Record 94619 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby electrical / panel (150 W Oak Knoll Dr): First appeared in published agency feed
Record B48927 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (111 Deer Hollow Rd): First appeared in published agency feed
Record B48924 · 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 $1,602,637 in September 2025 to $1,702,818 in September 2026.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94960 (not a parcel appraisal)
45 Oak Knoll Dr · 1 unit · $100,000 valuation
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
Annual ZIP 94960 home-value index checkpoint
Changed from $1,657,204 in September 2024 to $1,602,637 in September 2025.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94960 (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 →In "Applied" for 7.5 yr (since Apr 29, 2019), exceeding the 253d median and 686d 90th percentile for new single-family home permits in Unincorporated Marin (n=121). High-impact scale (1 housing unit, $1,000,000 declared valuation across 1 permit).
Active in "Issued" for 8.3 yr (first record Aug 9, 2018) with no new permit activity recorded in 7.6 yr. High-impact scale (1 housing unit, $1,097,000 declared valuation across 2 permits).
Active in "Issued" for 12.9 yr (first record Dec 24, 2013) with no new permit activity recorded in 12.4 yr. High-impact scale (1 housing unit, $800,000 declared valuation across 1 permit).
In "Applied" for 2.3 yr (since Aug 1, 2024), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
In "Applied" for 6 yr (since Nov 9, 2020), exceeding the 55d median and 261d 90th percentile for demolition permits in Unincorporated Marin (n=130).
In "Applied" for 5.8 yr (since Jan 13, 2021), 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 980 parcels
−11.8% YoY
City baseline: 16.4 / 1k
32 in trailing 24m
Includes 5 ADUs
| Builder / contractor | Primary specialty | Here / ½ mi | ½ mi valuation | Citywide 24m trend |
|---|---|---|---|---|
| Swan Pools | Pool / spa | 2 on parcel3 in ½ mi | $165,000 | 1 vs 4 prior |
| Simple Living | Remodel / interior alteration | 1 on parcel1 in ½ mi | $42,700 | 0 vs 1 prior |
| Jemico | Windows / doors / siding | 1 on parcel1 in ½ mi | $17,693 | 0 vs 0 prior |
| 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 94960
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 ($19,800/yr) + local voter-approved bond debt ($2,970/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.
−$112,762/yr
Cash needed: $435,600
NOI: $7,381/yr
P&I: $10,012/mo
For $0/mo net cash flow
At $3,650/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 | $3,358/mo | −$9,816/mo | -27.0% | $17,060/mo | −$9,854/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,650/mo | −$9,397/mo | -25.9% | $15,791/mo | −$9,227/mo |
| Optimistic (cap-limited) | +6% starting rent, 3% vacancy, 4.5%/yr rent growth (capped by AB 1482 ceiling of 8.6%/yr) | $3,869/mo | −$9,156/mo | -25.2% | $15,424/mo | −$8,751/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 new tankless water heater. — Replace Plumbing Fixtures(s)
Replacing 4 retrofit windows. like for like. — Non-structural Door/Window Replacement
Gas Line For Pool. ***161676
Kitchen Remdl
Pool To Include Gasline Line Installation T.D. 5/24/19
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
0.41 acres
Assessor's classification for assessment purposes. This is not zoning.
810 BUTTERFIELD RD
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 177-051-09. Assessed value is not market value.
Search by parcel number 177-051-09 (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.
| John Owens Services | Plumbing / water heater / sewer | 1 on parcel1 in ½ mi | $6,526 | 0 vs 0 prior |
| Owner Builder Recent nearby: 39 Legend Rd (Jun 1, 2026) | Remodel / interior alteration | 29 in ½ mi | $2,725,884 | 226 vs 240 prior−6% |
| Owner Recent nearby: 196 Deer Hollow Rd (Adu 196a) (Aug 28, 2025) | Remodel / interior alteration | 11 in ½ mi | $915,995 | 25 vs 15 prior+67% |
| Drake Building Recent nearby: 30 Fawn Ct (Mar 24, 2022) | Remodel / interior alteration | 5 in ½ mi | $655,000 | 1 vs 2 prior |
| First Impressions Painting And Building Recent nearby: 80 Oak Knoll Dr (Sep 7, 2022) | Remodel / interior alteration | 4 in ½ mi | $364,000 | 0 vs 0 prior |
| Schalich Brothers Construction Recent nearby: 1 Fawn Ct (Nov 17, 2020) | Demolition | 3 in ½ mi | $1,645,000 | 7 vs 1 prior |
| Dan Young Construction Recent nearby: 1111 Butterfield Rd (Apr 2, 2015) | Addition (adds square footage) | 3 in ½ mi | $973,000 | 0 vs 0 prior |
| 316 |
| 103d |
| 160d |
| 249d |
| 440d |
| 157d(vs 167d 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) |
| Pool / spaOn this parcel | 162 | 84d | 136d | 241d | 393d | 128d(vs 155d 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.