A clogged or blocked sewer line can cause a number of symptoms, including:

Slow drains
Drains in the sink, toilet, or bathtub that drain slowly, even after repeated attempts to clear the line.

Gurgling sounds
Air pockets in the sewer system can cause gurgling noises when using the dishwasher, washing machine, or toilet.

Foul odors
When wastewater doesn't flow properly, it can cause an unpleasant smell to come from anywhere in the drainage system, including the sink, toilet, shower, or tub.

Drains stop draining
Sluggish drainage that eventually stops completely can indicate a full obstruction.

Floor drain leaking sewage
Sewage backing up in the floor drain is a sign of a main drain clog that may require professional help to clear.