I'm installing a yard hydrant off my house water line (well water). The hydrant will sometimes be used for garden drip irrigation and so will be open for days or weeks at a time. The drip system itself has a plastic vacuum breaker that runs inline before the fertilizer injection tank.

Do I need an additional backflow prevention device just to be safe? If so, what kind? There seem to be multiple options, the cheapest being an extra AVB that installs on the hose, the most expensive being a pressure vacuum breaker - the type that is used for sprinkler systems. Do I need anything like this? If so, what and where? I was imaging something installed underground on the water line itself, but that doesn't seem to be common.

  • There are faucets with an integral backflow preventer. – Jim Stewart Jul 26 at 16:19
  • Hydrant style? I can't find any. – The Shoe Shiner Jul 26 at 16:54
  • Thanks, but that's a silcock. I need a hydrant that sticks up out of the ground. – The Shoe Shiner Jul 27 at 10:02
  • My 50 y/o house has two outdoor faucets on 1/2" copper tubing coming vertically out of the ground. When I last redid the valves I installed ball "garden valves" which have hose threads on the outlet side so I could attach hoses directly. I got brass anti backflow valves that thread on and have a small setscrew. I hope this does not damage the threads of the valve. These valves were a mistake, too hard to turn under pressure. I had to fashion makeshift wrenches to turn them. – Jim Stewart Jul 27 at 10:41

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