I have a house with a basement and I'm building a garage about 50 feet away in the backyard. The garage will be on a concrete foundation and I want to run both power and water out there. (I want the water for a mess sink and an exterior hose connection.)
My plan is to lay this pipe before the footings/foundation are put in. The water pipe will switch from copper to PEX inside the house, and the two pipes (electrical, water) will exit the house slightly underground, and then go deeper (probably 2-3' deep). They'll run up to where the garage footing will be, through a sleeve (4" pipe probably) that goes through the footing, and then be laid under the concrete foundation, poking up as close to the wall as I can. Because I'm relying on the water pressure from the house I was not planning on grading the water pipe, just running it level.
I do intend to install a blowout valve for the water pipe. There will be a ball valve in the basement of the house for this pipe, then the blow out connector, and then it will convert to pex and exit the house. In the garage, it will T under the foundation, one part coming up through the foundation, the other exiting the back side of the structure, through another 4" sleeve, and go into a below-ground graveled chamber with a ball valve shutoff, and a lawn sprinkler box top.
There will be no sewer connection, the interior sink will drain to a pipe that goes under the concrete and feeds out to that same gravel box, through the same sleeve. I know this precludes using the sink for things like washing out paint brushes and other chemicals; that's okay.
My first question is does anything sound off about this plan?
My second question is can I use PEX tubing for these water lines? I know you can't use PEX tubing where it will be exposed to sunlight; but I think I can bury it without problem. Can I also run it directly up through the concrete foundation without some additional protection?