how much does a gallon of water  weigh
The US gallon, which is equal to approximately 3.785 L, is legally defined as 231 cubic inches. A US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 Â°F (17 Â°C), making it about 16.6% lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes a US gallon equal to 128 fl. oz.