I don't see a problem.........
City water connection has an internal check valve so that water goes IN
Flush System has an anti-siphon vacuum breaker device so water goes IN
YES someone COULD open valve on manifold to flush system causing tank to fill/poop blow out roof vent.
Someone could hookup a hose to my flush connection and do the same
Someone could set fire to my rig
'What if' is always a possibility----I just don't get caught up.
My connections are on side of 5vr so I use a 'WYE' at hose bibb for multi-hose connections.
