San Anselmo 94960 · Sleepy Hollow · APN 176-042-06 · 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 $1,983,000 ($1,745,000–$2,221,000).
Zoned R1-BD supports ministerial ADU/JADU review plus SB 9 both two-unit development and ministerial urban lot split on a 22,738 sq ft lot. Local precedent is active with 1 ADU permit within ¼ mile over the last 36 months.
Source: Unincorporated Marin zoning · CA Gov. Code 66314 & 65852.21
On-parcel permit history is indexed through Apr 4, 2025, 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)
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: 1 homes completed.
1 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.
203 permits within ½ mile since November 2024
$1,983,000
Benchmark range: $1,745,000 – $2,221,000
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 40 De Burgh Dr (0.35 mi SW, 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 (~$1,938/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.
In "Applied" for 10.5 yr (since May 2, 2016), with no new permit record in 10.5 yr. · $2,500,000 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
In "Applied" for 9.3 yr (since Jul 31, 2017), with no new permit record in 9.3 yr. · 1 unit · $1,800,000 declared valuation
In "Applied" for 8.4 yr (since Jun 12, 2018), with no new permit record in 8.4 yr. · $500,000 declared valuation
Permit issued and active for 8.7 yr (first record Feb 21, 2018), with no completion or new permit record in 8.4 yr. · 1 unit · $800,000 declared valuation
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
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 ev charger (11 Catskill Ct): First appeared in published agency feed
Record B49048 · Detected between snapshots
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Snapshot diff within ½ mile
Nearby other (41 Katrina Ln): First appeared in published agency feed
Record B48947 · 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
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)
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)
HVAC / heat pump permit application filed (B41899)
Current status: Issued
REPLACE FURNACE IN SAME LOCATION — Replace Mechanical Appliance · Declared valuation: $3,718 · Contractor: Done Right Hvac Services Llc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
HVAC / heat pump permit issued (B41899)
Recorded status: Issued
REPLACE FURNACE IN SAME LOCATION — Replace Mechanical Appliance · Declared valuation: $3,718 · Contractor: Done Right Hvac Services Llc
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) · Geography: parcel
26 Irving Dr (Adu 26a) · 1 unit · $299,000 valuation
Records span May 10, 2024 to Dec 10, 2024 (1 permit).
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
15 Van Ripper Ct (Adu 15a) · 1 unit · $315,000 valuation
Records span Jun 6, 2024 to Oct 30, 2024 (1 permit).
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 $1,652,687 in September 2023 to $1,657,204 in September 2024.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94960 (not a parcel appraisal)
854 Butterfield Ln · $500 valuation
Source: County of Marin Community Development Agency, Building Permits (unincorporated Marin) & HCD APR (grouped project within ½ mile)
11 Katrina Ln (Adu 11a) · 1 unit · $575,000 valuation
Records span Feb 12, 2024 to Jul 24, 2024 (1 permit).
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 $1,730,005 in September 2022 to $1,652,687 in September 2023.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94960 (not a parcel appraisal)
26 Irving Dr · 1 unit · $200,000 valuation
Records span Jan 17, 2023 to Jul 31, 2023 (2 permits).
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 →In "Applied" for 9.3 yr (since Jul 31, 2017), 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, $1,800,000 declared valuation across 3 permits).
Active in "Issued" for 8.7 yr (first record Feb 21, 2018) with no new permit activity recorded in 8.4 yr. High-impact scale (1 housing unit, $800,000 declared valuation across 1 permit).
Active in "Applied" for 10.5 yr (first record May 2, 2016) with no new permit activity recorded in 10.5 yr. High-impact scale ($2,500,000 declared valuation across 2 permits).
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).
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).
In "Applied" for 3.8 yr (since Jan 17, 2023), 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 |
|---|---|---|---|---|
| James Petersen Industries | Roof replacement | 1 on parcel1 in ½ mi | $28,860 | 0 vs 0 prior |
| Done Right HVAC Services | HVAC / heat pump | 1 on parcel1 in ½ mi | $3,718 | 0 vs 0 prior |
| Arb | Other | 1 on parcel1 in ½ mi | $3,000 | 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 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 ($19,850/yr) + local voter-approved bond debt ($2,978/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.
−$113,123/yr
Cash needed: $436,700
NOI: $7,324/yr
P&I: $10,037/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 | −$9,846/mo | -27.1% | $17,102/mo | −$9,884/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,650/mo | −$9,427/mo | -25.9% | $15,829/mo | −$9,258/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 | −$9,186/mo | -25.2% | $15,462/mo | −$8,781/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 FURNACE IN SAME LOCATION — Replace Mechanical Appliance
extend gas houseline approx. 25' for mete4r relocation — New Gas Service
REROOF — ReRoofing
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
0.52 acres
Assessor's classification for assessment purposes. This is not zoning.
51 MARTLING RD
Source: County of Marin GIS (MarinMap), Parcels · Geography: parcel · Retrieved Nov 13, 2026
Search by parcel number 176-042-06. Assessed value is not market value.
Search by parcel number 176-042-06 (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: 39 Legend Rd (Jun 1, 2026) | Remodel / interior alteration | 32 in ½ mi | $5,464,926 | 226 vs 240 prior−6% |
| Owner Recent nearby: 170 De Burgh Dr (Mar 4, 2022) | Remodel / interior alteration | 9 in ½ mi | $617,995 | 25 vs 15 prior+67% |
| Redican Homes Recent nearby: 115 Hidden Valley Ln (Jul 9, 2025) | Addition (adds square footage) | 4 in ½ mi | $1,461,700 | 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 |
| Dan Young Construction Recent nearby: 114 Van Tassel Ct (Sep 1, 2016) | Remodel / interior alteration | 3 in ½ mi | $870,500 | 0 vs 0 prior |
| Marin Custom Builders Recent nearby: 101 Sleepy Hollow Dr (Jun 28, 2017) | Remodel / interior alteration | 3 in ½ mi | $595,800 | 0 vs 0 prior |
| Hettrich Construction Recent nearby: 310 Hidden Valley Ln (Aug 4, 2021) | Addition (adds square footage) | 3 in ½ mi | $572,000 | 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) |
| Roof replacementOn this parcel | 3,663 | 0d | 0d | 0d | 0d | 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.