If a drain is not used for an extended period of time, the water in the trap evaporates and the odor barrier is lost. A city crew will be dispatched to confirm whether the problem is in the city main. They will advise you accordingly. At this point you are responsible for any problems in your private line and may need to call a plumber. The most common cause of sanitary sewer line blockage is from root intrusion.
Roots grow into sanitary sewer lines searching for water and nourishment.
Roots can find their way into the smallest openings and begin growing and expanding, completely filling sewer lines and creating failures. These openings include pipe connections and cracks in pipes. There are two effective methods for removing roots in sewer lines. The first, and most common, is to use a blade to cut the roots out of the line. The second is to use a commercial herbicide that can be applied by the city.