It depends how long it takes you to shower
200 gallons 200 gallons 200 gallons
No, they cannot. Hamsters aren't supposed to be emerged in water. It is unnatural for them and can get them sick. If your hamster smells, get it a dust/sand bath. Normally, hamsters clean themselves...
he takes a rubber duckey
A long shower will take more water than a bath, but a bath will usually use more water than a short shower.