The main sewer line out of your home is an extension of your main stack line inside the house. It leaves near the foundation and connects up to the municipal sewer line near the street or into a septic system. When water backs up onto a basement floor, there is either a clog in the sewer service line, floor drain line or drain trap. Your service professional can do the work that will determine where the clog is.

If the clog is located in the sewer service line, the plumber may use a hand auger to clean it out. If the auger meets solid resistance, it could mean that the line is clogged with tree roots. In that case a power auger is the tool used.