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I'm going to run 3/4" PVC, underground, to my garden, to supply a drip irrigation system. The PVC will come straight up at the garden. I'll fit a hose bib on it, and thread on a backflow preventer. All of my hose bibs have them - I think they're required by the county.
I've done a couple of PVC repairs, and installed a new feed to a lawn sprinkler head. I feel comfortable enough to do the project myself.
I'm not sure where I should take the supply from.
This piping feeds the lawn irrigation system. The supply is to the right, and under the green cover is the box that contains the solenoids and water feeds to all the watering zones.
I'm not sure what the round thing on top is - I'm guessing backflow preventer.
Should I take my supply from here, maybe on the supply side? I could put a T on it, run the pipe horizontal so that I could put a shut-off on it, and the run it down into the ground.
I'll have a backflow preventer on the hose bib, so I'm assuming I don't need one on the supply to the bib.
I could take the supply somewhere to the right, from the underground pipe, but then I wouldn't have a shut-off, unless I ran it up out of the ground, like this one.
It would have been nice to have had a union after the shut-off, but it looks like the PCV is threaded directly into the shutoff. A "T" with separate shutoff values would have offered lots of options. One could even be a hose bib.
I would put a T after the existing backflow valve. Add another shutoff valve, then run the second PVC down, parallel to the existing and out to the garden
The only problem with that is if I have a problem with lawn irrigation, I have to shut off the supply, then I lose drip irrigation to the garden.
Where should I put the T? There isn't any room on the horizontal pipe - I would have to cut the pipe going down into the ground. Should I put the T in between the 2 couplers on that pipe?
If you put the T between the couplers, then the existing shutoff will stop flow to both the sprinkler system and your "new" drip irrigation.
Since there is a shutoff before the back flush valve, I would cut the PVC Elbow, remove the shuttoff after the backflow, install a T coming out of the backflow, and a pair of shutoff valves (one you already have).
Now, with elbows, couplings, and short lengths of PVC, connect one side back to the existing sprinkler, and the other to your "new" run.
So you will have a "master" shutoff before the backflow valve, then separate shutoff's for each output.
With both of these shut-offs turned off, AND the main to the house turned off, there's water pouring out of the backflow valve. The house has no water, so one of these shut-offs is obviously bad.
I'm not going to deal with it - I don't have the experience. I'm going to cut the down pipe on the irrigation side, install a T, put a shut-off after it, and run it down along side the irrigation pipes that are already there.
If the shutoff before the backflow did not stop the water, it may be completely corroded inside.
Had that problem in LA, CA. The presure regulator for the house had never been serviced, so screens, ball valves, etc. all eaten away inside. Had to replace the whole thing. And it was in front of the house supply shutoff - had to use a street-T at the meter to stop it until it was replaced. Still saved at least $100 by doing it myself.
