Our sewer has stopped up for the last two months. One theory is there is roots in our pipes. We use a balloon to clear the line from an outside cleanout. This works for a couple of days. Then, the line stops up again. Usually this occurs after a bath has been taken and a load of laundry has been done. Our laundry room floods as the washer drains. Could this be from a stopped up pipe that goes to the roof resulting in stopped water flow because there isn’t any air to push the water out?
Air does not push the water out, and a stopped up vent is seldom the cause of poor drainage. You probably have roots in the pipe which act like a porous sponge. When paper accumulates, it closes the pores and stoppage occurs. Using the balloon, forces the paper through the pores and restores drainage, but does nothing about the cause of the problem.