Here's the scoop. Whenever I aerate an irrigated lawn, I make the homeowner mark all the sprinkler heads and control boxes. Won't touch the lawn if not. In 3 years, that has worked fine. Until this year. In the spring I had a guy I aerated complain I broke his sprinkler line. Went to check it out. Sure enough, there was a hole in his sprinkler line. But the line was quite literally at the surface of the lawn. It was right under the surface of the grass. This fall, I've got another guy claiming I broke a line as well. This time the line was a bit deeper, but still right near the surface and not buried as deep as it should be. The guy in the spring had a landscaper put in a patio, and in the course of doing that they moved the lines and didn't bury them far enough. Not at all, actually. I refused to take responsibility for that. How am I supposed to know that if he didn't tell me, and how am I supposed to see under the ground for obstacles like that? This is why I ask to have things marked that I might hit. He got his landscapers to pay for it. The guy this fall though is being stubborn. He insists it's my fault. I am not sure how, as these lines are supposed to be buried deeper than the 2 or 3 inches the cores go. I ask to have the yard marked. I can't see through the ground, if something is down there, how am I supposed to avoid it? I have a feeling I'll end up paying the guy or fixing it to shut him up. But I've got to protect myself in the future against this. Does anyone use a disclaimer or waiver when they do aeration to protect against this kind of thing? I'm at the point where I am afraid to do aeration in irrigated lawns because it costs me more than I can make.