America's sewer lines are rapidly aging, with some more than 100 years old. As more homes have been connected to these out-of-date lines, sewage backups have followed.
Other sources of backups include pipelines that handle both stormwater and raw sewage -- and become overwhelmed in rainstorms -- and blockages from tree roots that work their way into sewer-line cracks.
When a sewer backs up into a home, it can damage floors, walls, furniture and electrical systems.
Walker says standard homeowners insurance does not cover sewer backups. If you are worried about being unprotected, she has some advice.
"Consider extra insurance that may be available as endorsements to your policy for risks such as sewer backups," she says.
The Insurance Information Institute says sewer-backup damage often can be covered for an additional premium of just $40 to $50 per year.