The answer
Whole-house repiping costs $4,000–$15,000+ depending on square footage, bathroom count, and accessibility (PEX runs $1.50–$3.50/ft installed; Copper runs $3.50–$8.00+/ft). Main water service lines cost $1,500–$5,000+ ($50–$250/linear foot). Requires local permits, pressure testing, and licensed C-36/C-34 contractors adhering to UPC/IPC codes.
Sources
This answer is drawn from the standards and guidance below. It is general information about how these systems work — not a diagnosis of your property.