A plumbing obstruction, also known as a CLOG, is a blockage in a pipe or drain that prevents the flow of water. Clogs can be caused by a variety of things, such as hair, grease, soap, and other debris. They can also be caused by tree roots or other objects that have become lodged in the pipes. Clogs can cause a variety of problems, including slow drainage, backups, and flooding. To prevent clogs, it is important to regularly inspect and maintain plumbing systems.