Applejack: Dressed? Uh, beg pardon, Rarity, but, uh… we don't normally wear clothes. The Best Night Ever. Season 1
In a culture where nudity isn't an issue, public bathing is a common occurrence in my Equestria dreamscape. That said a pony can still find it visually very interesting watch another pony bath. That whole wet mane look.
There's a proper bathroom inside the farmhouse at Sweet Apple Acres. However in barn there's a rudimentary shower that one can quickly rinse oneself off. By 1 in the afternoon Sweetie Belle wandered off back home and Stone Mane had finished his plowing chores.