Hi all this might be a silly question... but does anyone know how long you would have to run the water or have a shower to use up all the hot water in a 40 gal... 150 liter water tank

Thanks Roy

Roy, to completely deplete any hot (warmed) water would be dependent on the size of water line used, and the amount of water pressure that you have. Some people on a well with a 1" run in line and 1/2" line to the shower may take, lets say 20 minutes. But if you are on a public water supply and have the same size lines, but have a higher psi from the water source it may only take, lets say 16 minutes to run out of hot water.
As the hot water is removed from the tank, cold water is coming into the tank and "pushing" the hot water out of the tank.

Maybe a year ago, somebody here was reporting depleting a 30-40 gallon one in about 5 minutes.

Maybe a year ago, somebody here was reporting depleting a 30-40 gallon one in about 5 minutes.
Wow, to completely deplete ALL hot water in 5 minutes, they had to have some more pressure, but more than likely the tube that is attached to the cold water inlet had to have been with holes in it to loose all 30 to 40 gallons in 5 minutes.

Do you really think nobody here at the time thought to suggest that?