There's no definitive answer to this question - it really depends on the layout of your home and what you want to use the powder room for. If you have the space and you want to be able to use the room as a shower room as well as a powder room, then there's no reason why you can't install a shower in there. However, if you're limited on space or you only want to use the room for powdering your nose, then a shower might not be the best option. Ultimately, it's up to you!