Do toilet seat "washlets" (bidets) have back-flow prevention or vacuum breakers?

[Robert Gift]

The sprayer which moves forward under the user can become contaminated.
Does anything prevent contaminated water on the sprayer from getting syphoned back into the water supply?

Everyone should have a toilet seat bidet. Its many features makes it far better than a real bidet.

Thank you.

 

[Tuttles Revenge]

I know that Toto Washlets do have approved built in backflow prevention. I would be confident that other well known brands do as well. Toto washlets also have a cleaning feature every time the wand extends and retracts it runs water over the wand to clean it between uses. They also have a feature to manually extend the wand without spray for monthly cleaning.

Anything that is knock off on amazon I would suspect does not have approved backflow.