Gotta love 'em American preppers:
»Water weighs what, 8.9 pounds per cubic foot, a gallon of water weighs 8.5 pounds. I don't know what a liter weighs [...]»

Newsflash: "The gram, 1/1000 of a kilogram, was provisionally defined in 1795 as the mass of one cubic centimetre of water at the melting point of ice." - https://en.wikipedia.org/wiki/Kilogram#Definition
(that means 1 liter of water weighs - depending on temperature - more or less exactly 1kg)