The term 'drain problem' is often used to refer to a clogged drain, which is a common plumbing issue. A CLOG is caused when an accumulation of debris, such as hair, soap scum, and food particles, blocks the flow of water in a pipe. This can lead to slow draining, water backing up, and unpleasant odors. To fix a clogged drain, a plumber may use a variety of tools, such as a plunger, a snake, or a chemical cleaner.