Old or Damaged Sewer Lines
The sewer lines in older homes or neighborhoods may be made of clay or other materials that can crack or collapse over time. Any damage to these lines can lead to obstructions and subsequent backups.
Foreign Objects
Flushing inappropriate items down toilets, such as diapers, wipes (even those labeled as 'flushable'), feminine hygiene products, or excessive amounts of toilet paper, can cause blockages in the sewer lines.