[BB_TX]

I had an antisiphon valve leak years ago. But mine leaked because it was cracked. Unlike most all others I have seen, mine was clear plastic, so I could see thru it to the moveable “valve” inside. And it was just like the diagram I posted above. The moveable part was not spring loaded to hold it closed when not in service. It just fell to the closed position due to gravity. And there was no rubber seal to hold it watertight when not in service. Or for the moveable part to stick to and prevent it from opening under water pressure. Maybe the newer ones are different, but I don’t see any way the one I had could have ever completely blocked water flow.

If I remember correctly my hose connection in the convenience center had a check valve in it. If yours does, that could also be stuck.