I have a terraced drip irrigation system that is a few stories high. I’d like to put an automatic (but passive) drain valve at the bottom, so that when the system isn’t pressurized, the valve opens up and drains the water out of the system tubing into a cistern. But when the system turns on again, the pressure closes the valve, and it waters like normal.

I don’t know what such a valve is called though. I have searched amazon and the web under many different search terms, but am not finding what I want.

One thought... Could I use an anti-siphon valve (installed backwards?) to do what I want?

  • Why do you want to get rid of the pressurized system? How the heck do you imagine tons of water to be pushed up several stories high with out pressure? I have never had my own landscapes 'irrigated' with a system although I've installed them and taught people how to repair minor glitches and how to set their timers! I use the cheapest oscillating sprinklers for my landscape and lawns. They are the best for watering different types of plants, lawns thoroughly and properly. Slopes don't slough. Drip irrigation I've never found effective at all. You have no idea how deep the soil gets wet.
    – stormy
    Aug 12, 2019 at 0:48
  • Are you talking about a 'back flow device' at the beginning of your irrigation system? That has to be there. Is the source of your water at the top of those stories high beds?
    – stormy
    Aug 12, 2019 at 0:53
  • Sorry it hasn't worked for you. I've been drip irrigating for decades. Works great for me. I am not talking about a backflow device. And the device I found doesn't prevent the pressure. It just allows the lines to drain after the sprinkler cycle is over.
    – Emily Beth
    Aug 12, 2019 at 17:22
  • Yeah, I don't understand the parameters or specifics of what you are asking. I only installed irrigation, drip as well.
    – stormy
    Aug 12, 2019 at 20:50
  • Can you explain why you want to do this? E.g., what is the cost of leaving the water in the lines? You will spend energy and time raising the water twice.
    – Reid
    Aug 15, 2019 at 5:46

1 Answer 1


Wow! After much googling prior to posting this, I found the answer just minutes after posting. Here’s one thing that seems like it will work (in case anyone has similar question). I just wanted to keep the water that would go on my plants from baking in the sun all day in plastic tubing.


  • 2
    Check the specifications if your irrigation system is "a few stories high." You will get about 4 psi of water pressure at the bottom of a 10 foot high pipe just because of the weight of the water in the pipe, and that might be enough to stop the drain valves opening if they work in the 3 to 5 psi range. You might need separate drain valves for each "level" of the system.
    – alephzero
    Aug 11, 2019 at 20:24
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    Very good point, the valves in the link close at 5psi, a "storey" is generally 10', water column is .5 psi per foot (or thereabouts), so... they might not open even if placed on each level... Aug 11, 2019 at 20:28
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    I have used similar vales from another manufacturer and they have not been reliable. I have very low head pressure. Aug 11, 2019 at 21:33
  • @JimmyFix-it, I think they should open, at least in theory. The higher one will open and drain the higher elevations, and then when the higher elevation is drained the head pressure will be lower, and the lower valve will open and drain. Now, whether these valves actually work or not, we'll see...
    – Emily Beth
    Aug 12, 2019 at 17:24
  • @alephzero: Yep, I need two of these for my application. Although the mfr sells only packs of 10 (it seems), I got some individual valves on ebay, so it will be an inexpensive experiment, if nothing else. I'll report back on how well (or not well) this works.
    – Emily Beth
    Aug 12, 2019 at 17:26

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