I assume that you are asking about replacing the water distribution pipes. Cost depends on how difficult it is to access the pipes, and on how many plumbing fixtures are in your house. I'd budget at least $3,000 to $4,000 plus the cost of repairing and repainting any wall covering that would need to be removed to gain access to pipes in the walls and ceilings. This assumes a common three bedroom, two bathroom house on a crawlspace or basement. Cost may be more if there are water distribution pipes in a concrete slab.