Question
We recently bought a home that has a lake-fed sprinkler system.  We believe there are some problems with the valves, but don't know where the valve box is located.  The control box is located in the garage, and my husband dug all along that wall, with no success.  Is there any way to determine where the valve box would be?

Answer
If they are buried, then its going to take some detective work to find them.  Get a shovel or a probe of some kind, and start looking for areas that may be a little greener than others, spots where it might be a little more moist, or where the grass grows better than other places.  Probe around until you hit something.