Some of that is going to depend where the pipe is -- is it in your house, or running under the sidewalk?

I have a fairly old house, so the roto rooter guy has to come once a year to snake out the pipes. If he broke one in the basement, it would be on (my particular) homeowners' insurance.

But if the trash guys dropped something that broke through the sidewalk outside, that's the city's problem.

Your particular policy should tell you what the limits are.