JohnDar
Prolifically Gabby Member
If the water is running down the pipe from above, in the wall cavity, it's probably the anti-siphon valve (ASV). In a word, they're plastic garbage. In your shower, there should be an access port in the wall under the faucet fixture. You may be able to reach the valve there, depending on your floor plan. If that's the culprit, you can replace it with a brass one.
Some of us, where the faIled ASV was stuck up a wall cavity with no access, ripped them out and used a brass check valve, instead.
Some of us, where the faIled ASV was stuck up a wall cavity with no access, ripped them out and used a brass check valve, instead.