Hi, sprinkler system design newbie here.
I was ecstatic to find out that the water company in my community will install a second water meter for free to supply my irrigation system. However, my question is how to design for winterization of the mainline from the downstream side of the new water meter up to the side of the house (to be buried below frost line ~36" deep) where my PVB backflow device will be installed above ground. The tutorial at www.irrigationtutorials.com indicates that a manual drain valve is a cross-connection no-no prior to the backflow device so i am curious how to drain the portion of the mainline where it rises out of the ground to the PVB?
Right now my only thought was to install a tee in the mainline down below the frost line which rises to a capped nipple. Then, after the water meter was isolated and the line bled of pressure, the cap could be removed and the vertical portion of the mainline up to the inlet of the PVB could be blown out with compressed air. What isn't clear to me is whether the capped nipple would also constitute a potential cross-connection according to code (I am hoping it would not since it is capped without a valve and it shouldn't qualify as a use point).
I wouldn't be surprised if there is a simpler/better way to deal with this that I am unaware of. Anyone else designed for a similar situation?