Which statement is true about the weight of a gallon of water?

Which statement is true about the weight of a gallon of water?

• A. One gallon of water weighs about 8.3 pounds
• B. One gallon of water weighs about 12 pounds
• C. One gallon of water weighs about 5 pounds
• D. One gallon of water weighs about 15 pounds

Answer: (A)

The weight of a gallon of water is controlled by density. A US gallon is 3.785 liters, and water’s density is about 1 kilogram per liter at typical temperatures, giving roughly 3.785 kilograms. That converts to about 8.34 pounds, so saying a gallon of water weighs about 8.3 pounds is the best approximation. Temperature changes only tweak this slightly (water is densest near 4°C), but 8.3 pounds per US gallon is the standard figure used in field calculations. The other weights would correspond to different liquids or a different gallon definition, not water in a US gallon. This handy rule of thumb helps with quick estimates in salvage operations, such as weighing water to gauge loads, pump capacity needs, or line friction considerations.

The weight of a gallon of water is controlled by density. A US gallon is 3.785 liters, and water’s density is about 1 kilogram per liter at typical temperatures, giving roughly 3.785 kilograms. That converts to about 8.34 pounds, so saying a gallon of water weighs about 8.3 pounds is the best approximation. Temperature changes only tweak this slightly (water is densest near 4°C), but 8.3 pounds per US gallon is the standard figure used in field calculations. The other weights would correspond to different liquids or a different gallon definition, not water in a US gallon. This handy rule of thumb helps with quick estimates in salvage operations, such as weighing water to gauge loads, pump capacity needs, or line friction considerations.