There is a 4" diameter plastic pipe with a cap sticking out of the ground about 5 feet from the foundation of my house. Curiosity got the best of me and I removed the cap and looked down the pipe and I could see water moving at the bottom of the pipe. What is the function of this standpipe outside the house, and should it be something more substantial than a piece of PVC sticking up out of the ground?
This standpipe is in the yard for maintenance purposes and supplying air into the sewer pipes for free flowing reasons, and with modern plumbing practices it is normal for it to be made from PVC.
Its use is for having the pipe cleaned or snaked from outside the home rather than making a mess inside if a clog were to happen. If it is in the way of yard work, it is OK to cut it off flush with the ground so that a lawnmower can clear it, but make sure it does not get lost in the grass. Try and keep the vent grate open for air getting into the sewer system.