Hempstead Lake at Hempstead water level — New York
Hempstead Lake at Hempstead in New York was last measured at 22.24 ft (datum NAVD88), as of Aug 31, 2026, 2:00 AM (UTC-05:00) (USGS Water Services). Over its recent trend window the level has been rising (+1.0 ft). This reading is provisional and subject to revision.
- % of conservation pool full
- Not reported
- Storage
- Not reported
- Recent trend
- ↑Rising
+1.0 ft over the trend window
Recent trend
Readings this station published between Jun 2, 2026 and Aug 31, 2026 — a 89-day window — downsampled for display.
Data: USGS Water Services (waterservices.usgs.gov) and USACE CWMS Data (cwms-data.usace.army.mil), retrieved 2026-08-31. Both public domain (a work of the U.S. Government, 17 U.S.C. §105).
Source: USGS site 0131079450, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for this lake →
About this gauge's record
This site's drainage basin covers approximately 17 sq mi of contributing watershed.
The dam behind Hempstead Lake at Hempstead
Hempstead Lake at Hempstead is held back by Hempstead Lake Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 24 ft high and running 1,200 ft along its crest , built across MILL RIVER in Nassau County , near Rockville Centre . It was completed in 1873 , and is owned by NYS OFFICE OF PARKS, RECREATION & HISTORIC PRESERVATION- LONG ISLAND REGION (a state owner) .
Its recorded primary purpose is recreation — holding a stable pool through the season is an operating goal, so a level well off normal in summer is unusual rather than routine .
Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. The spillway opening is 24 ft wide.
NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. Its most recent condition assessment was satisfactory — no deficiencies recognised for expected loading. That assessment is dated 01/23/2025.
At its normal pool the reservoir covers about 149 acres. NID records a maximum storage of 1,220 acre-ft against a normal storage of 470 acre-ft. Its maximum discharge capacity is 323 cubic feet per second. It is regulated by NYS DEC.
Dam facts: National Inventory of Dams record NY00108 , filed by New York — U.S. Army Corps of Engineers, public domain. Water levels above come from USGS Water Services and are a separate source. (How this dam was matched to this gauge →)
How Hempstead Lake at Hempstead compares nearby
1 of 6 nearby lakes with a current trend are also rising right now.
Nearby lakes
The six nearest published lakes by centroid distance (great-circle) — cross-state neighbors included.
| Lake | State | Level | Distance |
|---|---|---|---|
| Baisley Pond at South Ozone Park | NY | 5.67 ft | 12 km |
| Clove Lake at Sunnyside, Staten Island | NY | 129.96 ft | 39 km |
| Ohrback Lake at Richmond, Staten Island | NY | 249.70 ft | 41 km |
| Oradell Reservoir at Oradell | NJ | 23.04 ft | 45 km |
| Lake Tappan at Old Tappan | NJ | 55.10 ft | 49 km |
| Woodcliff Lake at Hillsdale | NJ | 94.74 ft | 51 km |
Frequently asked questions
- What is the current water level of Hempstead Lake at Hempstead?
- As of Aug 31, 2026, 2:00 AM (UTC-05:00), the pool elevation was 22.24 ft (datum NAVD88), provisional and subject to revision. See the trend chart above for the recent direction.
- Is Hempstead Lake at Hempstead full right now?
- Its managing agency does not publish a %-of-conservation-pool-full figure for this lake, so we show the bare level rather than estimate one.
- Where does this data come from?
- From USGS site 0131079450, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00).
More in New York
See every lake tracked in New York, or read the methodology behind these figures.