Question
I came home one day to find that one of my zones was on and had been on for a few hours consistent with all the water flowing in the gutter.  The only way I could turn that zone off was shutting off the main sprinkler water valve inside the house.  I checked the electrical at the timer and in the valve box and all seems to be fine.  Bad zone valve? Thanks in advance.

Answer
A few things could be wrong. You timer could have a hot terminal. That means the terminal were your zone wire hooks up is always on. Next the solenoid on your valve could be faulty or dirty. Last your valve needs to be cleaned. All of the above could cause your zone to stick on.