My pool is still new and was completed in late July 2015. I have a 4" pvc drain pipe running from the patio down the side of my house out towards the street. Wednesday night we had severe rain and the pool overflowed and deck backed up. Mud got in the pool. Big mess. We came close to getting water in the house. There are 5 drains on the patio and an overflow drain on the pool as well. I have 2 gutters the pool builder ran into the same drain due to the location of the downspout. The drain cap is one of those NDS pop ups. Water was gushing so much the cap eventually blew off. I've never had issues before. None of the drains are blocked or clogged. Water just couldn't get out fast enough. I'm thinking the pop up drain cap initiated the problem due to restriction under heavy load. Once the rain let up everything drained off quick. Anyone ever have this kind of issue?