Flood damage is not typically covered by a homeowners insurance policy.
If a house is destroyed due to the collapse of the land it is built on, and the collapse is due to waves or currents of water, that would be considered a flood and would be covered.
There are some homeowner endorsements that will cover a back-up or overflow of sewers or drains or a sump-pump. These type losses sometimes do occur during flooding events. These endorsements will often have dollar limits substantially less than the flood policy
Voluntary flood insurance policies are not enforced until 30 days after purchase.
Collapse or subsidence of land and the insured house, along a shore of a body of water caused by waves or currents of water are considered a flood and are covered by this policy.