Whether it's tree roots in the main sewer line, a backed-up floor drain, a kitchen sink not draining, garbage disposal not working properly, or maybe a slow drain, the Drain Plumber can fix it. If you have a drain problem but are not sure what it is, we can find out exactly what is going on. Who is Responsible for the Main Sewer Line? Most homes' main sewer lines are connected to the city sewer system beneath the street in front of their home. So if it's part of the city's system, doesn't that mean the city should pay for any repairs or sewer line replacement?