Who ever put this system in, They used high end parts, like the controller and the solenoid valves. The valves are Irritrol 100 series that go for 75 bucks a copy, and I have 12 of them. I replaced a diaphram ($18) and a soliniod ($8) and still the valve was passing water. This is what started me on the slupply side. That being said, one would think they did it properly. Well ...it is obvious that they did not if I cannot shut the damn thing off. All 12 valves (12 stations) are in the far back of the yard in a row. I was thinking that I should start digging around there to find the supply to them. There is a hillside above that has some valves operating, so the valve is the lowest part of those stations. I heard anti siphon valves do not work if they are not the highest of the parts. So, when I find the supply near the valves, I will put a ball valve and maybe some other valve to make sure water does not go back to the house?