Castro Valley 94552 · Castro Valley · APN 85-1613-21 · Unincorporated Alameda County
No permit activity recorded within ½ mile.
$1,573,000
Benchmark range: $1,384,000 – $1,762,000
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.
We don't have building permits for Unincorporated Alameda County, so we can't show what has been permitted nearby.
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 Alameda County's planning department before relying on it.
Sources: City of Oakland Planning & Building, Zoning (base zones, effective 2024-12-17) (retrieved Oct 26, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the State Responsibility Area (effective 2024-04-01) (retrieved Oct 26, 2026) · CAL FIRE Office of the State Fire Marshal, Fire Hazard Severity Zones in the Local Responsibility Area (map dated 2025-03-24) (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — flood hazard zones (retrieved Oct 26, 2026) · FEMA, National Flood Hazard Layer — FIRM panels (retrieved Oct 26, 2026) · California Geological Survey, Alquist-Priolo Earthquake Fault Zones (retrieved Oct 26, 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 4.9 yr (first record Dec 17, 2021), with no completion or new permit record in 4.9 yr. · 1 unit
Permit issued and active for 4.4 yr (first record Jun 15, 2022), with no completion or new permit record in 4.4 yr. · 1 unit
Latest published Zillow Home Value Index (ZHVI) update
Changed from $1,351,445 in September 2025 to $1,364,641 in September 2026.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (not a parcel appraisal)
Annual ZIP 94552 home-value index checkpoint
Changed from $1,402,125 in September 2024 to $1,351,445 in September 2025.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (not a parcel appraisal)
Annual ZIP 94552 home-value index checkpoint
Changed from $1,314,882 in September 2023 to $1,402,125 in September 2024.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (not a parcel appraisal)
Source: Alameda County building permits & HCD APR (grouped project within ½ mile)
Annual ZIP 94552 home-value index checkpoint
Changed from $1,370,155 in September 2022 to $1,314,882 in September 2023.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (not a parcel appraisal)
Annual ZIP 94552 home-value index checkpoint
Changed from $1,264,101 in September 2021 to $1,370,155 in September 2022.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (not a parcel appraisal)
Source: Alameda County building permits & HCD APR (grouped project within ½ mile)
Building permit reported to State HCD for 1 housing unit (BLD2021-03210)
Reported in 2021 Housing Element Annual Progress Report
ADU · Renter
Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: parcel
Annual ZIP 94552 home-value index checkpoint
Changed from $982,440 in September 2020 to $1,264,101 in September 2021.
Source: Zillow Home Value Index (ZHVI) · Data provided by Zillow · Geography: ZIP 94552 (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 Alameda County development graph →Active in "Issued" for 4.9 yr (first record Dec 17, 2021) with no new permit activity recorded in 4.9 yr.
Active in "Issued" for 4.4 yr (first record Jun 15, 2022) with no new permit activity recorded in 4.4 yr.
HUD Small Area Fair Market Rent · ZIP 94552
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 ($15,750/yr) + local voter-approved bond debt ($3,465/yr) + fixed direct levies/Mello-Roos ($450/yr).
Mapped hazard zone insurance context on this parcel:
−$87,419/yr
Cash needed: $346,500
NOI: $8,150/yr
P&I: $7,964/mo
For $0/mo net cash flow
At $3,350/mo 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 | $3,082/mo | −$7,670/mo | -26.6% | $13,788/mo | −$7,695/mo |
| Base (your inputs) | Your entered assumptions, 3.0%/yr rent growth | $3,350/mo | −$7,285/mo | -25.2% | $12,762/mo | −$7,120/mo |
| Optimistic (cap-limited) | +6% starting rent, 3% vacancy, 4.5%/yr rent growth (capped by AB 1482 ceiling of 8.6%/yr) | $3,551/mo | −$7,064/mo | -24.5% | $12,466/mo | −$6,683/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.
Issued1 unitsDec 17, 2021 – Dec 17, 2021
We group related permits and State housing reports into projects. That grouping is our inference, not an official record.
No building permits are recorded for this parcel since 2016.
| Report year | Project / record | Type | Entitled | Permitted | Completed | Deed-restricted |
|---|---|---|---|---|---|---|
| 2021 | —(BLD2021-03210) | ADU · Renter | — | 1 (Dec 17, 2021) | — | — |
Source: California HCD, Housing Element Annual Progress Report — Table A2 · Geography: project (parcel) · Retrieved Oct 26, 2026 · From Unincorporated Alameda County's Housing Element Annual Progress Reports. A project can appear in several report years as it moves from entitlement to permit to completion.
Source: City of Oakland Planning & Building, Zoning (base zones, effective 2024-12-17) · Geography: zoning district polygon at parcel point · Retrieved Oct 26, 2026
0.29 acres
Assessor's classification for assessment purposes. This is not zoning.
18540 GREENRIDGE CT
Source: Alameda County Assessor / Information Technology Department, Parcel Boundaries · Geography: parcel · Retrieved Oct 26, 2026
Look up assessed values and parcel maps by parcel number 85-1613-21. Assessed value is not market value.
Search by parcel number 85-1613-21 (Alameda County Treasurer-Tax Collector)
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.