Date Range: 12/1/09 - 3/1/10

Notes:

• The "natural rim" of the lake is 6223 feet above sea level. That is the lowest level at which water will continue to spill over the dam at Tahoe City and into the Truckee River, the only outlet of the lake.
• Upward spikes in the graph represent periods of high run-off into the lake, generally immediately following a storm.
• Up to one-tenth inch of water, or 330 million gallons, can evaporate from the lake on a summer day.
• Remarkably, each half-foot of lake level represents over 20 billion gallons of water, enough to supply 105 million people with their average daily needs!
• The average level of the lake is 6225 feet above sea level. The highest recorded level was 6,231.26 feet on July 14 -18, 1907. The lowest level ever recorded was 6220.26 feet on November 30, 1992. The maximum level now allowed by law is 6229.1 feet.
• Graph updated on the 2nd and 16th of every month.
• Data courtesy of the Department of the Interior, U.S. Geological Survey.