Lake Tahoe, straddling the border of California and Nevada in the Sierra Nevada mountains, is celebrated for its remarkable clarity and deep blue waters. Lying at an elevation of over 6,200 feet, it holds the distinction of being the largest alpine lake in North America. The sheer quantity of water it contains is perhaps its most astonishing characteristic. Quantifying the physical dimensions of this ancient lake reveals the colossal volume held within the Tahoe Basin.
The Staggering Volume of Lake Tahoe
The total quantity of water residing in Lake Tahoe is approximately 39 trillion gallons. This immense figure ranks it as the sixth largest lake by volume in the United States, trailing only the five Great Lakes.
This volume translates to about 36 cubic miles of water, or over 122 million acre-feet, providing a scientific context for water management. The sheer magnitude of this water body means its profound depth allows it to store a colossal amount of water, despite having a surface area relatively small compared to other great lakes.
The Physical Dimensions Defining the Volume
The incredible volume of Lake Tahoe results directly from its deep, block-faulted basin structure. The lake’s maximum measured depth is 1,645 feet, making it the second deepest lake in the United States. This deep trench, formed by ancient geological forces, contributes significantly more to the water volume than its surface footprint.
The average depth across the lake is 1,000 feet, underscoring its great capacity. The surface area covers approximately 191 to 192 square miles. Water enters the lake from 63 different tributaries, but only one, the Truckee River, serves as the single natural outlet. The entire watershed, which funnels precipitation and snowmelt into the lake, covers about 312 square miles.
Putting Tahoe’s Water Volume Into Perspective
The 39 trillion gallons can be better understood through direct comparisons to human-scale metrics. If the entire volume of water were spread evenly across the state of California, it would cover the state to a depth of about 14 to 14.5 inches. This illustrates the vastness of the reservoir contained within the mountain basin.
Lake Tahoe holds nearly four times the maximum capacity of Lake Mead. Furthermore, every 24 hours, the lake loses a significant amount of water to evaporation, enough to meet the daily water needs of several million people if recovered.
The enormous volume also dictates the lake’s water residence time—the period required for all the water to be completely replaced by inflow and outflow. For Lake Tahoe, this time is estimated to be between 600 and 700 years. This extremely long residence time means the water is not quickly flushed out, making the lake susceptible to pollutant accumulation and highlighting the role of its depth in maintaining purity.