Please note that policys vary from insuring company to insuring company, and from state to state, so you must read your policy and talk to your agent to know what your particular policy covers.
In general, a full coverage replacement cost homeowners policy will cover the resulting water damaged from a pipe break as defined as sudden and accidental exposure to water. What this means is that if you had a water loss, and did not repair it, or were not aware of the leak and the water caused rot or deterioration, then the insurer will probably deny the claim. If you have a water loss that was sudden and accidental - meaning it happened today or within a reasonable period like a week or so, then the resulting damages caused by the water, and the expensed to clean it up may be covered. What is generally not covered are the repairs to the actual item that caused the water damage. This is usually the actual pipe that broke, the washing machine hose that blew, the water heater tank that failed, etc. Now when I refer to resulting damages from sudden and accidental discharge, I can give you this example. A pipe broke in the wall behind your kitchen sink. The water from the pipe flooded the kitchen and living room of your home. The cabinetry in the kitchen is all warped, your vinyl floor in the kitchen is discoloring as the water got under it, and the hard wood floors in your living room began buckling. The drywall in your kitchen and living room is showing water staining. In this scenario, with a full coverage type homeowners policy that carries replacement cost, the insurer will most likely cover the emergency extraction of the water, the dryout of the home, the tearout and replacement of wet damaged building materials, and the access to the pipe that broke. What they would not pay for is the pipe repair itself.
As I stated above, please remember that every insurance carrier is different, and policies and laws differ from state to state and carrier to carrier. Read your policy and don't get blindsided by what is or is not covered on your insurance policy.