Hetch Hetchy Reservoir

Name: Hetch Hetchy Reservoir (California) water level
Creator: U.S. Geological Survey

at Hetch Hetchy, CA · California · USGS gauge

Water level · NAVD88

3,758.01FT

Gauge elevation · no % full published

7 days −2.90 ft30 days −12.97 ftvs last year −1.43 ft

Reading for Oct 25, 2026, 18:00 UTC · page refreshed Oct 25, 21:16 UTC
Source: U.S. Geological Survey (Water Data for the Nation)

Worth going today?Today

Looks good

Light wind, dry

Wind5 to 10 mph

Rain2%

Temp74°F

Level3,758.0 ft

TodayMostly Sunny · 74°F
SW 5 to 10 mph · rain 2%

TonightPartly Cloudy · 44°F
NE 0 to 5 mph · rain 2%

NWS forecast for the gauge location. Good = wind ≤ 10 mph and rain ≤ 30%; storms are flagged. Not safety advice – check local conditions, closures and warnings.

Field notes

As of Oct 25, 2026, Hetch Hetchy Reservoir stood at 3,758.01 (NAVD88) ft.

Over the past 7 days the lake has been falling (−2.90 ft), and it is −12.97 ft over 30 days.

Compared with a year ago (3,759.44 ft, same time of day), the lake is 1.43 ft lower.

Readings come from the USGS gauge “HETCH HETCHY RES A HETCH HETCHY CA”. Gauge elevations are not directly comparable between lakes because each uses its own datum.

Lake facts

Gauge / station	HETCH HETCHY RES A HETCH HETCHY CA
Elevation datum	ft (NAVD88)
Gauge location	37.9477, -119.7879

Nearby lakes

Lake Eleanor5 mi W4,653.53 ft−0.09 ft Cherry Lake7 mi W4,683.12 ft−0.04 ft Beardsley Lake24 mi NW3,334.80 ft−6.40 ft Donnell Lake28 mi N4,791.51 ft−2.89 ft Don Pedro Reservoir39 mi SW784.80 ft−2.04 ft

Common questions

Is Hetch Hetchy Reservoir rising or falling?

Over the last 7 days it changed −2.90 ft and over 30 days −12.97 ft.

How full is Hetch Hetchy Reservoir?

USGS publishes the water surface elevation for this gauge but not a percent-full figure, so we don't show one rather than estimate it.

How often is this page updated?

The page is rebuilt automatically every day from USGS's published data. Values can be revised later by the source agency.

Where does the data come from?

The U.S. Geological Survey's Water Data API (api.waterdata.usgs.gov), which publishes readings from USGS and partner gauges. Forecasts come from the National Weather Service.

Latest instantaneous reading; 7-day, 30-day and year-ago changes compare readings at the same hour. USGS data are provisional and subject to revision. This page is not affiliated with or endorsed by the USGS. See data sources.