How Much Does Water Weigh?

If out of the blue, someone asked you how much water weighs, you may be confused. Water is a liquid, and liquids are typically measured in volume, not weight.

There is no constant weight for water. As the temperature changes, the weight of water changes. Also, without dissolved substances, water weighs less. But with dissolved substances like salt and sugar, water weighs more.

A gallon of water equals approximately 16 cups of water and weighs 8.33 pounds at room temperature. The same quantity weighs 8.45 pounds at 39.2 °F and 8 pounds at the boiling point (212 °F).

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Different Types of Water Measurements

A liter of water equals 0.264 gallons of water (approximately 4.2 cups of water). A liter of water weighs 2.2 pounds at room temperature.

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An acre-foot is the unit of measurement for water that is impounded or stored. An acre-foot of water equals 325,851 gallons of water. At room temperature, one acre-foot of water would weigh about 2,713,974.056 pounds.

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