When the temperature of the water is 4°C, 1 cubic foot of it (1,728 cubic inches)
weighs 62.428 pounds, and that weight is not going to change when the water
freezes.
1 US fluid gallon = 231 cubic inches
( 231/1728 of a cubic foot) x (62.428 pounds per cubic foot) = 8.345 pounds (rounded)
(If that water were warmer than 4°C, then each gallon would weigh less,
both before and after it freezes.)
A half gallon of water weighs approximately 4 pounds.
8 pounds of water in 1 US gallon
1 gallon of water weighs 8.2 pounds, so 32.8 pounds
63,844.1 pounds.
80 gallons of water weighs about 668 pounds (about 8.35 pounds per gallon).
One US gallon of plain water weighs 8.34 pounds.
4
8.33
705 gallons of water weighs about 5,883.2 pounds.
30 cubic feet of water at 8.34 pounds per US gallon equates to ~1,871.63 pounds of water.
About 8.4 pounds.
Approximately 8.3 pounds.