The backup of water or waterborne materials through a sewer or through a drain 

Water or waterborne material that overflows from a sump, even if the backup of water is due to the mechanical breakdown of the sump pump. Coverage includes damage to covered property but excludes the sump pump and any related equipment that has broken down 

Paper products: Do not flush anything other than toilet paper down your drain.  

Cooking grease: Instead of rinsing grease down your drain, dispose of cooled grease in your garbage. 

Shrub and tree roots: It’s common for the roots of trees and shrubs to make their way into sewer line cracks. Over time, the cracks allow debris to build up. If you have continuing problems with tree roots in your sewer lateral, consider replacing it with a pipe made of plastic.  

Illegal plumbing connections: Connecting flood control systems to your sanitary sewer only spells trouble. Consult a plumber to correct any illegal connections.