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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

arinte
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  • 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](https://www.amazon.com/dp/B0039ZE2HK/ref=cm_sw_r_cp_api_K5IYAbPQN47Y3) made for o-rings. Does your state require annual re-certification of Backflow preventers by a certified Backflow inspector? Most states do. – Tyson Apr 08 '18 at 15:04
  • How does one verify that a back-flow preventer is operating properly? – Jim Stewart Apr 08 '18 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 08 '18 at 19:01
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    @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 08 '18 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. – Jim Stewart Apr 09 '18 at 14:32
  • @Tyson where are you located? – Jim Stewart Apr 09 '18 at 14:41
  • @JimStewart you must not have familiarity with underground irrigation systems, a quick google shows that [TX has virtually the same backflow regulations](https://www.tceq.texas.gov/drinkingwater/cross-connection) as my state, Missouri. I kind of thought it would because one problem area that creates backflow is sunshine heating water (expansion) in surface or shallow lines (that’s why garden hoses/faucets are an issue). BTW, most meter yokes DO have a check valve to help prevent backflow, but it doesn’t count as a backflow preventer, and is not regularly inspected device. – Tyson Apr 09 '18 at 15:01
  • @Tyson, we do not have an irrigation system on our urban lot (10,000 sq ft), but I am aware that they are required for and are actually installed on irrigation systems in Dallas. We do have screw-on backflow preventers on the two outside faucets. I am very relieved to know that water meter "yokes" have check valves to prevent backflow. I hope these yokes are in a location which is inaccessible and so not easily tampered with or bypassed. The supplied water pressure in Dallas is about 50 psig and there is no need for pressure reducers. – Jim Stewart Apr 09 '18 at 16:28
  • My comments were based on what I now realize is surely a wrong assumption on my part. I thought the backflow preventer in the question here was for the water supply of the *entire house*. I just realized that the OP is referring to his irrigation system only. (I was wondering about the PVC water pipes, but didn't draw the conclusion.) – Jim Stewart Apr 09 '18 at 16:35

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