What is the average weight of a gallon of water in kilograms?

A gallon of water weighs approximately 3.785 kilograms. The average weight often cited for a gallon of water is around 3.6 kilograms, considering different types of gallons (U.S. liquid gallon or imperial gallon) and other variables like temperature.

Choosing 4.2 kilograms likely reflects a misunderstanding since it overestimates the weight of a U.S. gallon. It’s essential to recognize that the standard U.S. gallon is about 3.785 kilograms, and rounding to 3.6 kg provides a practical reference point that simplifies communication and calculations in various applications, including septic systems and water-related calculations.