I had sewer water backup into a shower. Had a plumber out to snake the line. This did not clear up the issue of standing water in the sewer line. He ran a video camera down pipe and found that two different sections had standing water. He tells me this is not normal and the solutions is to use a digital camera with a locator head to map the "bellied" sewer pipe. Then cut through the slab to replace the pipe.

The house is a slab on the ground type with a septic system. All plumbing is under the slab. The pipes are pvc. Is this really the only solution? The plumber says improper ground prep is the most likely cause of the "bellies"