seems we are assuming it the water backed up as a result of a failed sump pump. damage that results from water backing up from a drain, which a sump pump is, is excluded on all homeowners policies. you have to buy the coverage back and/or have the policy endorsed to cover this type of loss. a good agent will just included it in a quote or package and not really bother mentioning its an added endorsement.
insurance carriers do this because this type of loss is frequent, especially in the midwest.
battery backups are good. however, with enough rain and an extended power outage it will only delay the flooding.
good luck Scummer.
later.