Repiping is the process of replacing the plumbing network in a home or commercial building. There can be several reasons for repiping. Sometimes an aging system can create lots of problem on continual basis. Old water pipes can start leaking or may contaminate the water. Use of ineffective material is another reason for doing repiping. For example, polybutylene pipes can fail without any warning and are ineffective where they have been installed. 
Today polybutylene pipes are not used in buildings, but may need replacement wherever they’ve been used earlier. Sometimes PVC pipes also fail to function in a proper way. Some types of brass fittings may also fail once they are dezincified. This can pose danger to the property and water supplies. A thorough inspection and repiping can easily prevent such problems from occurring.
The first and most important step in repiping a building is an in-depth inspection. This will help the plumber in assessing the extent of the job to be done. Sometimes simple pipe repair will get the desired results. However, if cast iron or lead pipes have been used, they will have to be removed and more invasive pipe replacement will be needed.
A complete repiping of the entire plumbing network in any building will include all waste water and potable water piping. New cold and hot distribution and branch pipes are also included. The plumber will issue a quote after inspection. This quote would include the cost of all material to be used and labor.
May not include the cost of any new fixtures unless you request that they be installed during the repiping process.
Preparations for repiping is the next step in this process. You may have to make some down payment before the work begins. The entire system will be planned in the beginning and all the materials will be purchased by the plumber. You will also get a detailed notification on ways to protect their belongings and furnishings during the repiping process. The floors, ceiling, and the walls are cut open for exposing the older pipes. The main water line is turned off and all pipes that were unsightly or in the way are removed. So expect to be without water for a few days!