Rainfall: Heavy periods of rainfall can cause sewer lines to overflow with large amounts of groundwater and storm water, resulting in a backup.
Blockages Due to Tree Roots: Shrubs and trees seeking moisture can make their way into sewer line cracks causing extensive damage. As the tree or shrub continues to grow and the roots expand, they can create blockages.
Sanitary Main: In some cases, a blockage can occur in a city sanitary main. After some time, sewage can back up into homes and businesses.
Grease: Pouring grease, fats, and oils down your drain will bring about a back up once the grease cools and attaches itself to the walls of the sewer pipe. Other objects flowing down the drain will stick to the grease and eventually block the pipe.
Toilet Paper and Foreign Objects: When too much toilet paper, paper products, or foreign objects are flushed down the toilet, it will eventually result in a blockage and then backup