text:  That's where at the end of the year you can turn off the main valve and then drain it down from there. In the box that's right next to that, in the rectangular one, that is your backflow preventer, which needs to be installed where it is. That's really good. That's a below ground one. You don't have the big pipe coming up above ground. It's a more expensive valve that needs to be tested every year to make sure that it's working fine.