When it comes to indoor plumbing why not have a Super Mario-themed bathroom sink? You got your mushroom handles, a Warp Pipe faucet, and a Piranha Plant that acts as the lever for the drain plug thingy. You could also enlist a Chain Chomp to act as a drain stopper for an older sink.

Note: it’s not very apparent here, but on top of the mushrooms are round-shaped H and C letters to indicate hot and cold water.