How much does a gallon of water weigh, in pounds?

A gallon of water weighs approximately 8.3 pounds at its maximum density, which occurs at around 39.2 degrees Fahrenheit. This weight is a standard reference used in various fields, including firefighting, where understanding the weight of water is crucial for calculations related to water supply and usage during emergency response situations. Knowledge of this fundamental property helps firefighters estimate the total weight they may be dealing with during an operation, especially when transporting or pumping water.

The other choices do not accurately reflect the weight of a gallon of water. 6.2 pounds is too low and does not account for the actual density of water, particularly at the relevant temperatures. Similarly, 4.7 pounds and 2.1 pounds underrepresent the weight, as they stray even further from the accepted value. Understanding these weights is vital for operational efficiency and safety in firefighting activities.