What Causes a Sewer Backup?

Sanitary sewer overflows can be caused by a number of factors. They usually involve sewer pipe blockages in either main sewer lines or service laterals (lines between buildings and the main line).

Causes may include:
  • Construction mishaps
  • Insufficient system capacity due to residential or commercial growth
  • Pipe breaks or cracks due to tree roots
  • System deterioration

Home & Office Plumbing

In home and office plumbing systems, the main cause is accumulation of grease, tree roots, hair or solid materials, such as disposable diapers or sanitary napkins that are too large for wastewater pipes to handle.

Such materials may cause major backups in City lines as well as in residents' lateral lines. A frequent cause of water stoppages within the City's system, however, is vandalism. Leaves, sticks, rocks, bricks and trash have been found stuffed down manholes. We hope you will report observations of any such activity.

View the Fats, Oils, and Grease (FOG) (PDF) document for more information on these things can affect your sewer.