I'm helping a friend with a small house in an area that freezes and we're plumbing the supply side in such a way that the lines can be gravity-drained. There is a low point where the line from the well connects to the building supply which will need a drain. Plenty of ways to do it but I think the simplest will be a drain line which is trenched below the frost line with a mechanical valve. Not difficult to make something up but I'm wondering if there is an available product that does this? A ball valve with a handle that can be run up a bit of pipe, sort of like a city water shutoff valve but about 3' deep. I don't want to use an electric solenoid, needs to be mechanical.