What to Expect from Sewer Line Repairs? The sewer line is so important. This pipe runs a few feet under your yard and is what connects your household pipes to the city or municipal sewer main. These four- to six-inch pipes transport all of the waste and wastewater generated by your household. Though they are made of relatively sturdy material, the pipes are susceptible to damage. Though they are made of relatively sturdy material, the pipes are susceptible to damage. There is no time to waste when it is time for a sewer line repair, but it would help to know what to expect, right?