I installed the Delta Atmospheric Vacuum Breaker today and it did not work like I hoped it would. The shower head still dribbles after the water is shut off. There has to be a way to fix this though. It is totally unacceptable.Most municipalities require a backflow preventer but you need an Atmospheric Vacuum Breaker (AVB)
"An AVB is a non-testable mechanical backflow preventer with a gravity opening poppet air opening, designed to admit atmosphere into the downstream sides of the unit under a no flow condition to prevent back-siphonage."
The literature says this:
Vacuum Breakers are required by many municipal governments to protect the drinking water from being contaminated by water from swimming pools, lavatory sinks, bath tubs, or toilets. It is an atmospheric-type back flow preventer. The seating and unseating of the diaphragm are accomplished by the presence or absense of water pressure, when the unit is open to the atmosphere. It is normal for the vacuum breaker to emit a small amount of water:
a) During the opening and closing of the shower control valve.
b) When used with a massage action, may emit water when changing spray selection.
c) When used with a push button shower, water may emit out of the unit when the shower is placed in the off position.
It is normal for the vacuum breaker to drain when it is placed lower than the hand shower, and the water is shut off.
The unit screws on to the water supply where your hose is connected now and then you screw your hose onto the breaker. It's inline with your hand held shower head.