[BB_TX]

Probably not much in the case of an RV. But it is almost always a requirement that any connection that is in any way connected to “dirty” water and connected to a public water supply that that system must have some means to prevent any possible backflow or dirty water into that public water system. Lawn sprinkler systems is s common example. The vacuum breaker valve or anti siphon valve is there to prevent any possibly siphoning of dirty water into the clean water system.