No, it's never justified. If you're worried about your water and sewer lines, self-insure by putting $7.99 in the bank every month. By the time your lines need fixing -- if indeed that ever happens, which it may well not -- you'll have plenty. Bonus: you'll also have money in case the roof leaks, there are plumbing problems, electrical problems, the water heater needs to be replaced, or what have you... Or you could just keep an emergency fund. In short, this deal is a rip-off. It might help one in a hundred thousand people who happens to need the service when they have the insurance. But the odds against needing it are huge.
I did have to have my sewer line replaced a few years ago. (Installed in 1924, a tree had grown into it.) I used my emergency fund. Problem solved. That's one sewer line problem in 35 years, or $3355 worth of insurance payments, had I bought insurance, not counting interest on the money. The repairs cost under $600.