What is the “Backup of Sewers or Drains” endorsement? Do I need this if I already have Homeowners insurance?

Answer:

The standard Homeowners Insurance policy excludes coverage for the backup of sewer/drain lines, as well as the failure of a sump pump, so companies like Pioneer State Mutual often offer a “Backup of Sewers or Drains” endorsement.
 
When sewers and/or drains back up, normally damage occurs in the basement, which houses the mechanical systems of the house, such as washers and dryers, furnaces, hot water tanks and the numerous items people store there. Water or sewage usually destroy anything they come into contact with, so having this type of endorsement could prevent you from paying for the entire incident out of your own pocket.