Many homeowners use the term "flood" to describe any situation where there is water in a home, whether it came from a roof leak, plumbing leak, air conditioner malfunction, or elsewhere. Most of those sources of water are covered under your regular homeowners policy, but a true "flood" is excluded.
A "flood" according to the National Flood Insurance Program (NFIP), is a "general and temporary condition where two or more acres of normally dry land or two or more properties are inundated by water or mudflow." Flooding typically occurs where it has rained and drainage is insufficient, excessive tides have occurred for any number of reasons, or a storm surge has brought water that isn't normally present.
In order to be covered for flood damage, you must have a separate insurance policy that covers you for flood. It may be part of the NFIP, administered by FEMA and the Federal Government, or it may be a private flood policy, although this is quite rare.
Flood policies are significantly different than a standard homeowners insurance policy and there may be significant gaps between your flood coverage and your homeowners insurance. It's best to consult an agent before you encounter this situation to make sure you have the most comprehensive coverage possible.
If you suffer a flood loss, remember you are going to be dealing with the federal government, and it's also likely that you are one of many people making the claim, so the process can be slow.
VIP Adjusting has handled flood claims related to a number of storms, including Hurricanes Frances, Jeanne, Wilma, and Irma.
For a little bit more entertaining, yet informative view on flood insurance, we'd like to share with you a John Oliver segment explaining FEMA and the NFIP (Warning: Strong Language)