Dedicated supply line or tee off existing supply line
I am trying to renovate a sprinkler system on an older house. The sprinkler that the previous owners installed wasn't very good, so I am redoing it.
My plans are to start with the front yard this year or early next year and depending on how it goes do the back and side yard the year after. I am trying to get at least the supply line put in this year, or at least the parts that will be in the front yard so I can plant next year and not have to disturb the plants.
I was planning on using a 1" PVC for all the supply lines to the various valve boxes in the front, back and side yard. I plan on using fertigation so I need to install a backflow preventer.
To start out I yanked out the old sprinklers in the front yard and dug out the junction point for the existing supply line. It is tee'd into the water going into the house. It appears to be either 1/2" or 3/4" iron piping, I attached a photo.
So I have a few questions:
1) Is it best to have a dedicated line from the water main for the sprinkler?
2) If the line from the main is 1/2" or 3/4" iron piping, does it make sense to have 1" PVC for the supply lines?
3) If a dedicated line is best, how much would you expect to pay to have it installed(the water main is 25' directly south in my parking strip and my front yard is yanked up and free of cables/obstructions).
Any help is appreciated.