I've been running my system a lot because we just overseeded the lawn. I
think that I may have an underground leak in one of my zones. The area in
question is really wet, all the time. It's next to the sidewalk, and that
is always wet too. Almost like the wetness is coming from under the
concrete.

I'm pretty sure I have a leak, but can't see compelling evidence of it.
(like water peculating up through the ground)
Does anyone have a good way to find or check for leaks without digging the
whole thing up?

Thanks,
Joe Michel