If a city water line bursts and results in a flood to your property,  is there coverage under your homeowner policy for the damage?............No  it is not.
A flood can result from a water source other than storm and hurricane activity.   This type damage would also be covered with a flood policy. 
A flood is "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 your property)