You’ll be pleased to hear that bidets do not use toilet water. Instead, the water is routed from your home’s fresh water supply. This water will either be hot or cold, depending on the model of bidet you’re using.
For bidet toilets and bidet toilet seat attachments, this water comes from the water line located behind the toilet — the same supply that fills the toilet tank. This is also the same water that flows into your bath, shower and sink.
If you’re using a standalone bidet, the water will come from the exact same water line — but it won’t be as simple as attaching it to an exposed pipe that’s already in use. It’ll be channeled into the wall, requiring a plumber.
Hot water bidets can work in two ways: They can either be channeled into your home’s hot water supply, or they’ll syphon off some water and store it in a tank within the bidet that an electrical element will then heat.
If you’re using a hot water bidet, it will also need to be connected to your home’s cold water supply as it’s a ratio between hot and cold that allows you to set the temperature — the cold water cools the hot water to your preference.
But regardless of what setup you’re using, bidet water is always clean, and it always comes straight from your home’s clean water supply. It’ll never come from the toilet bowl. It’s the same as your drinking water, so it’s completely sanitary.