Thanks must be the UK "gallon" that is 4.5 litres.
Semantics anyhow.
When USA fuel approx doubles from where it is currently, then the USA will have caught up to aussie prices.
Enjoy a road trip while you can (it is cheap in USA right now.)
This is what a backflow preventer looks like. Not always red, not always this big, but you will see them all over town…