sub pump install

also im open to suggestions on how to connect 3 sub pump lines. I was planning to install 3 sub pumps and use 2" pvc to discharge the rain water. i wanted to come up along the wall the with the pipes and connect all 3 pipes, then drill a hole through the wall and run the pvc pipe the length of my yard into the woods. i was told to install a safety valve on each line closer to the sub pumps to prevent back up of water......

I would not tie the drains together. I would take them up above ground and drop the pipes down into a single 4" or two 3" underground drains and maintain an air gap at the junction. If you put checkvalves inline, you need to be concerned about the lines freezing.