Many people mistakenly use the term Flood when describing damage from a pipe break but the insurance companies definition is very specific and in order to be covered for both you actually have to have two separate policies. Pipe breaks and water damage from a plumbing system are covered under your standard HO3 homeowners policy.

Flood loss is covered under a separate Flood policy and is defined by the Federal Emergency Management Agency as:
A general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of two or more properties (at least one of which is the policyholder's property) from:

• Overflow of inland or tidal waters; or
• Unusual and rapid accumulation or runoff of surface waters from any source; or
• Mudflow;or
• Collapse or subsidence of land along the shore of a lake or similar body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels that result in a flood as defined above.

If you do not have a specific Flood policy for your property then you are not covered under the government's definition of a flood loss. Your homeowner's policy excludes loss coverage from Flood.

The following link will help you understand Flood coverage.
http://www.fema.gov/library/viewRecord.do?id=3011