I have a brand new house. If the frost free hose bib with anti-siphon is turned in the on position and either a sprinkler or sprinkler timer is installed, water drips out from the bottom of the valve stem. What would be the cause of this? I know that there is back pressure on the anti-siphon but should it leak?

Thank you.

Michael

I have a brand new house. If the frost free hose bib with anti-siphon is turned in the on position and either a sprinkler or sprinkler timer is installed, water drips out from the bottom of the valve stem. What would be the cause of this? I know that there is back pressure on the anti-siphon but should it leak?

Thank you.

Michael
Yes it will leak with back pressure. An anti siphon device is designed to prevent "backflow" or "back pressure" so your potable water system doesn't get contaminated. Look into the item you have attached and see if there is any type of water saving device that can be removed.