Instructions said to make sure a backflow preventer is present, or else install a vacuum breaker. Does the 75704 have this?
Thank you for your question on the Delta Universal Showering 7-Setting Hand Shower. I would love to help answer your question! Most Delta hand showers include back flow prevention unless stated otherwise in the installation guide or technical specifications sheet. If your hand shower is engraved with "ASME a.112.18.1" it does have back flow prevention. I hope this was helpful! If you have any other questions or concerns about this product you can give us a call at 800-345-3358 for answers and assistance.
Delta Faucet Company
Date published: 2018-01-19