In this picture I have a spigot in point 9 (see the spigot setup below) and I am planing to install an irrigation system as per the below layout

The edging is 44'x18' with flower beds ~4' wide (at their widest point) What size should my red pipes be and what size should the blue pipe be considering that the copper pipe that comes out of the wall is 1/2"? Can I use a hose with a quick connect from the spigot (❾) to the manifolds (❽) which I plan to remove during the winter?

How deep should I dig for the pipes? The frost line is 3-4' in Toronto so I guess it does not make any difference if it is 6", 1ft or 3ft. I have the feeling that the installation depth for these pipes is dictated by a compromise between avoiding accidental digging out the pipe when doing something else and saving on materials

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the spigot and the PSI at spigot level enter image description here

1 Answer 1


If you supply your system via a spigot, the size of the supply pipe upstream of the spigot becomes irrelevant because you will be limited by the port size of the spigot (or any attachments to it; e.g. that gated wye).

The system supply requirements are dependant on all that is downstream of the supply. In other words, you cannot know what is needed until you determine what type of nozzles, emitters, soakers, sprinklers, etc. will be in use simultaneously, down the line. That is how you calculate the GPM you need vs. GPM available. Most systems as large as what you are planning need to be set up in seperate zones, which are not operated at the same time, for sufficient water delivery. It is nice that you posted the static supply pressure, as that is an important part of the equation, but you need more data.

Note: it would be advantageous for you if you removed the existing spigot and placed a tee in the supply line, then used a full-port ball valve to supply your system (whether hose supplied or directly piped) because that would give you more water than trying to squeeze through the restrictions in the spigot (and appurtenances like that gated wye).

  • Yes each umbered belw 8 is a zone by itself.Full bulb sounds like a good idea However I will still need to be able to connect a hose ther. Maibe at 8 where the manifold is and avoid any more dripping in that corner between garage and hous point 9 I am still unclear if using a hose between 9 and 8 is advisable
    – MiniMe
    Jun 14, 2020 at 17:05
  • Using a garden hose as a seasonal connector should not be a problem. It would be best to purchase a high quality reinforced rubber hose, rather than a cheap vinyl one... Jun 14, 2020 at 17:36
  • Sorry for the typos above, low battery on my bluetooth keyboard. OK I will proceed with the sizing of the zones and then get back to this. As a general guidline, should I aim for a larger pipe downstream of the full bulb spigot or for a 1/2" all the way (in which case using a hose might not be possible)? I remember reading something about pressure loss when changing the diameter
    – MiniMe
    Jun 14, 2020 at 19:37
  • What do you think about the answer to my other question gardening.stackexchange.com/questions/52613/…
    – MiniMe
    Jun 14, 2020 at 19:45
  • I do not understand that question... Jun 15, 2020 at 5:16

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