15 William Ave
Islip, NY 11751
5 bd 2 ba 2,000 sqft Built 1965 Lot 5,227 sqft single_family
No recorded sales
Location
Timeline: Sale, Listing & Tax History
Recorded events
No recorded events
No sale or listing events are on file for this property.
Tax assessment history
| Year | Building | Land | Total assessed | Tax paid |
|---|---|---|---|---|
| 2025 | $34,000 | $5,500 | $39,500 | $13,725 |
| 2024 | $34,000 | $5,500 | $39,500 | $13,019 |
| 2023 | $34,000 | $5,500 | $39,500 | $13,019 |
| 2022 | $34,000 | $5,500 | $39,500 | $13,007 |
| 2021 | $34,000 | $5,500 | $39,500 | $12,585 |
| 2020 | $34,000 | $5,500 | $39,500 | $12,253 |
| 2018 | $34,000 | $5,500 | $39,500 | $11,916 |
| 2017 | $31,550 | $5,500 | $37,050 | $11,125 |
| 2016 | $31,550 | $5,500 | $37,050 | $11,058 |
| 2015 | $31,550 | $5,500 | $37,050 | $8,751 |
| 2014 | $31,550 | $5,500 | $37,050 | $8,622 |
| 2013 | $31,550 | $5,500 | $37,050 | $8,410 |
| 2012 | $31,550 | $5,500 | $37,050 | $8,075 |
| 2011 | $31,550 | $5,500 | $37,050 | $7,749 |
| 2010 | $31,550 | $5,500 | $37,050 | $7,393 |
| 2008 | $31,550 | $5,500 | $37,050 | $7,097 |
Property facts
Year built
1965
Property type
single_family
Stories
—
Beds
5
Baths
2
Living area
2,000 sqft
Lot size
5,227 sqft
ZIP code
11751
City
Islip
Street
William Ave
Coordinates
40.73762, -73.21029
Comparable properties nearby
Frequently asked questions
When did 15 William Ave last sell?
No public-record sale is on file for 15 William Ave.
What is the current tax assessment for 15 William Ave?
The most recent total assessment for 15 William Ave (year 2025) is $39,500 with $13,725 in property tax.
When was 15 William Ave built?
15 William Ave was built in 1965.
How does 15 William Ave compare to others on William Ave?
We track 3 other properties on William Ave. Browse the list under "Other properties on William Ave" to compare beds, baths, and sale history.
What are the property facts for 15 William Ave?
15 William Ave is a 5 bed, 2 bath, 2,000 sqft, 5,227 sqft lot single_family.
Is 15 William Ave a flip candidate?
No — 15 William Ave does not appear in our flips dataset.
Is 15 William Ave a tax-appeal candidate?
No — 15 William Ave is not currently flagged as a tax-appeal candidate.
Forecast for this area
ZIP-area linear projection — not a per-property automated valuationQuarterly trend
-13.7%
Implied 1-yr
-54.6%
2026 Q1
$212.6K
2026 Q2
$212.6K
ZIP 11751 — Median Price History + Forecast
Explore nearby
Geography
Other properties on William Ave