Picture water rising out of a basement floor drain or a toilet after a heavy storm. It is unpleasant, it can be expensive to clean up, and it is often not covered by a standard homeowners policy unless you have added a specific endorsement for water backup or sewer backup.

Because this is not flood damage in the usual sense, some homeowners assume it falls under their regular coverage. In many policies it does not. The endorsement is usually optional and often modest in cost, but it typically comes with its own limit, so check how much it would actually pay toward cleanup, flooring, drywall and damaged belongings.

If you have a finished basement, a sump pump or older sewer lines, this coverage deserves a careful look. Ask your insurer whether you already have it, what the limit is, and whether a failed sump pump is included. If your current insurer offers only a small limit, it is reasonable to see what other companies include when you compare quotes.