I've noticed that a small area in my lawn puddles with water after I irrigate it -- the lawn sloshes when I walk across it. This leads me to wonder whether there's a break in my PVC supply line, or perhaps at one of the sprinkler risers. (I use Rainbird 1800 3" pop-up sprinklers.) Nowhere else in the landscape does the water puddle, and the spot where it is puddling is just as flat as anywhere else (not in a depression or anything). I've had lines break on me before, but usually there's a telltale lack of water pressure near the break. In this instance, everything seems to be working fine. Is there any way to detect A) whether there is indeed a break in the line somewhere, and B) how to pinpoint where the break is without digging up the entire lawn?