Abstract: Disclosed is a system and a method for reducing or eliminating lead and other harmful materials in water. The system is configured for fluid flow where the system includes: a semi-rigid pipe (SRP) disposed inside a first existing pipe; two coupling assemblies disposed over and sealingly coupled to the ends of the SRP. Each assembly includes: a coupling with a nipple configured to receive and be disposed inside the SRP; and a compression nut that includes an inner surface that tapers inward such that threading the compression nut onto the coupling presses the semi-rigid pipe against the nipple to form a fluid-tight seal.