Along the same line of thought, is there a good method to "discover" and map out the irrigation system. I bought a house and therefore inherited an irrigation system that has obviously been patched a time or two. I'd like to be able to identify the PVC and zones beyond just turning on the water. Do professionals have some kind of detector that I could rent etc...?
Regarding finding the valves, isn't there enough metal in the the valve/solenoid for the metal detector to work? I've found that valves are not neccessarily located with any ryme or reason. Some are all together near the water source and timer box, others are distributed all over the yard with long wire runs etc... good luck