Try and save some backache by doing some testing before you dig. I am guessing you have never had one a part so I'll try and explain some of this as I go. Those things functions by a big rubber plunger on the end of the rod that slides up and down when you move the handle. Where the handle pulls on the rod is adjustable, usually by a set screw. I found when I moved into my place that all my hydrants were out of adjustment. If the handle is locked into place too high, it will usually allow more flow through the hydrant. This is fine except that when you shut it off, the rubber plunger does not not travel far enough down to uncover the weep hole for the excess water to drain back out. This allows everything to freeze up. Once I adjusted all my hydrants, they worked fine, they just had less flow. You can test this really simple when they thaw out. Run the water out for a few seconds and then shut it off. IMMEDIATELY put you hand in front of the faucet. If it is draining you should be able to see and hear the vacuum of the water as it siphons back into the ground. I dug a hydrant out for no reason to find out the hard way to fix the issues. Might fix you, might not, but I'd rather you not dig if you don't have to.