Perfect World
Hydrology Metering

Hoover Dam · Colorado River · NV–AZ

Lake Mead

The largest reservoir in the United States by capacity, and the one with no active USGS gage — the Bureau of Reclamation's daily record is its only public measure.

Water surface elevation

1,038.8 ft

Bureau of Reclamation, daily · daily value, Aug 31

Water in storage

6.90 million acre-feet

Bureau of Reclamation, daily · daily value, Aug 31

Share of capacity

26.4% full

against the 1964 survey capacity figure (USBR Hoover Dam project data (1963-64 area-capacity survey basis))

Below full pool

180.8 ft

full pool at 1,219.6 ft

This month in the record

the lowest September in 89 years of record

monthly mean storage; record low 7.28 million acre-feet (2022), record high 29.06 million acre-feet (1942)

30-day trend

-5,116 af/day

storage, 2026-07-312026-08-30; over the year -3,244 af/day. Measured change, not a forecast.

Drought at the dam

D1 — Moderate drought

US Drought Monitor at the dam's coordinates, released 2026-08-27; the feeding basin can differ.

Water flowing out

2,267 cfs

operator's daily release, 2026-08-31

full pool 1,220 ftdead pool 895 ft1,039

26.4% full

of capacity, by storage (1964 survey figure, USBR Hoover Dam project data (1963-64 area-capacity survey basis)). Sedimentation slowly shrinks real capacity.

The water line is elevation (USBR project datum); the percentage is storage ÷ capacity. They are different measures — a reservoir's volume is not linear in its depth, so the line's height in this column is not the percentage.

Snowpack in the feeding basin

Measured across the Upper Colorado basin snowpack that feeds the whole Colorado system upstream.

Snow season

typically Oct 12 – Jun 12

0 in on the ground, 2026-09-01; median peak 19.7 in around May 3

Last winter's verdict

47% of median peak

water year 2026 — the snow that fed this year's pool

5 highest active SNOTEL stations in the basin (Black Mesa, Slumgullion, Castle Peak, …), NRCS AWDB REST (SNOTEL), station set pinned 2026-08-31. Daily snow-water equivalent against the stations' own 30-year medians; off season the percent is withheld rather than divided by zero.

The last 120 days

Daily water-surface elevation in feet. The axis hugs the data — it does not start at zero. Source: committed snapshot (USBR RISE, retrieved 2026-08-31).

1036.91047.21057.5May 3Jul 2Aug 301038.9
See the numbers as a table
DateElevation (ft)
Aug 301038.87
Aug 291038.87
Aug 281038.89
Aug 271038.94
Aug 261039.05
Aug 251039.16
Aug 241039.23
Aug 231039.27
Aug 221039.31
Aug 211039.38
Aug 201039.44
Aug 191039.55
Aug 181039.66
Aug 171039.77
Aug 161039.79
Aug 151039.76
Aug 141039.70
Aug 131039.78
Aug 121039.82
Aug 111039.95
Aug 101040.09
Aug 91040.24
Aug 81040.34
Aug 71040.40
Aug 61040.50
Aug 51040.61
Aug 41040.72
Aug 31040.85
Aug 21040.96
Aug 11041.06

Most recent 30 days shown.

The whole record

Monthly mean elevation, Feb 1935 to Aug 2026. The axis spans the pools, not zero; elevations in USBR project datum. Months with fewer than 15 gaged days are dropped, and gaps in the record break the line. Source: USBR RISE, retrieved 2026-08-31.

monthly mean elevationpool reference lines
6659601,256Feb 1935Nov 1980Aug 2026full pooldead pool1,040
See the numbers as a table
MonthMean elevation (ft)Days gaged
Aug 20261039.830
Jul 20261042.431
Jun 20261047.030
May 20261053.031
Apr 20261059.230
Mar 20261064.631
Feb 20261065.828
Jan 20261063.931
Dec 20251060.931
Nov 20251057.630
Oct 20251057.731
Sep 20251056.630
Aug 20251054.731
Jul 20251054.631
Jun 20251055.830
May 20251059.531
Apr 20251064.030
Mar 20251067.631
Feb 20251067.728
Jan 20251065.131
Dec 20241062.031
Nov 20241061.030
Oct 20241063.131
Sep 20241063.630

Most recent 24 months shown; the full monthly series is in the page's API response.

Storage against capacity

Monthly mean storage in acre-feet, zero baseline. The dashed line is the 1964 survey capacity figure (USBR Hoover Dam project data (1963-64 area-capacity survey basis)) — sedimentation slowly shrinks real capacity. Storage can legitimately rise past a conservation-pool line when the flood pool is in use.

monthly mean storagecapacity
015.7M31.4MJun 1937Jan 1982Aug 2026capacity7.0M
See the numbers as a table
MonthMean storage (acre-feet)Days gaged
Aug 20266,963,88930
Jul 20267,140,93231
Jun 20267,464,83230
May 20267,900,43031
Apr 20268,362,97830
Mar 20268,774,01531
Feb 20268,870,10028
Jan 20268,724,97531
Dec 20258,492,78531
Nov 20258,239,13330
Oct 20258,251,55431
Sep 20258,166,47330
Aug 20258,025,11431
Jul 20258,016,26631
Jun 20258,105,76730
May 20258,385,24031
Apr 20258,733,67530
Mar 20259,006,61831
Feb 20259,018,68528
Jan 20258,816,64031
Dec 20248,572,64431
Nov 20248,503,25630
Oct 20248,659,47531
Sep 20248,701,91230

Most recent 24 months shown.

Where these numbers come from

Readings at Lake Mead are the measuring agencies' own: each value above names its source (USGS gage, Bureau of Reclamation daily record, Army Corps project data, or this desk's committed copy) and its observation time in the reservoir's own time zone. The capacity figure is the 1964 survey USBR Hoover Dam project data (1963-64 area-capacity survey basis) number; sedimentation slowly shrinks real capacity, so the vintage travels with the percent.