I am going to reattach my backflow preventer today (save 125 vs calling company). Do I need to apply any plumber grease or pipe glue to the pvc portion? Here are some pics of the preventer and place to attach it.

Close up of PVC Backflow Outside pipes

  • Your o-rings, which pop out easily, are still present. (Black rings on the fittings in the grass.) I would pop those off and clean them and apply a silicone lube made for o-rings. Does your state require annual re-certification of Backflow preventers by a certified Backflow inspector? Most states do.
    – Tyson
    Apr 8, 2018 at 15:04
  • How does one verify that a back-flow preventer is operating properly? Apr 8, 2018 at 18:41
  • @JimStewart I will find out tomorrow as I have a guy coming to test it as specified by the city.
    – arinte
    Apr 8, 2018 at 19:01
  • 1
    @JimStewart I don’t know the exact procedure because mines underground and 2 people can’t really look down into the pit at once, but there are 4 test ports (blow up op’s second pic and you can see them) a pressure gauge is attached to one port, and then a hose connected between two others, somehow black-flow is simulated using mainline pressure. Although I blow my irrigation system out myself and start it back up I still end up paying a service call every year for the backflow test, the results/form must be sent to the water dept, or they shut you off.
    – Tyson
    Apr 8, 2018 at 20:00
  • Dallas does not require customer installed backflow preventers and AFIK we do not have them unless they are part of the water meter, which I doubt. I wonder how many public water supply systems require them. Apr 9, 2018 at 14:32


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