Lake Michigan has an estimated volume of 1,108 cubic miles or 6 quadrillion gallons of water. It provides over a billion gallons of drinking water a day .
Lake Michigan is the sixth-largest continental lake in the world and the second-largest Great Lake by volume. Technically, Lake Michigan and Lake Huron are a single lake, which makes them the largest freshwater lake in the world by surface area. However, the two lakes are commonly considered separate and are divided by the Strait of Mackinac.
Like all lakes, Lake Michigan's volume varies slightly depending on factors such as precipitation, but the difference is small enough to be insignificant. Its volume is enough to fill 24 trillion bathtubs, which is almost 3,000 bathtubs for every person on Earth.