Sewer line replacement is covered by standard home insurance policies as part of other structures coverage, which protects structures such as sheds, garages and detached carports that do not have separate insurance. Sewer line damage falls under dwelling coverage, but it may have a limit of 10% of your home’s insured value. It depends on your policy’s details.
Most homeowners policies include coverage for damage to the sewer line due to fire, lightning, hail or windstorms, explosions, vehicles or aircraft, falling objects and vandalism.
The important thing to note is that your policy only covers damage caused to a sewer line if it was from a specific event (such as listed above), and the damaged pipes must be on your property line.
You can also often get coverage for sewer backup, water lines, sump pumps, etc., up to a certain limit by purchasing the appropriate endorsement in addition to standard coverage.