If you mean how much does it hold when entirely full, it can't be answered without knowing the size. If you are asking how much is used, again without know how long you let the water run or how many minutes, this can't be answered either.
Approx. 15 to 20 litres are used in a single shower
To fill a container that can hold 100 litres, you would need 100 litres of water.
Only as much as some one allows the water to run
4.5 litres
About 10 litres
18 litres
A US gallon is 3.785 litres. An Imperial gallon is 4.54 litres
It would hold 5.7 litres, obviously!
10 Litres
8 litres
it is around 3 million litres
7,3 litres