A pre-action fire suppression system was installed in a portion of a US Army Reserve Component Headquarters building in the Southeastern United States, when the structure was constructed in 1995. A pre-action fire suppression system, which is normally kept at a standard internal air pressure using air compressors in the basement electrical-mechanical room, is designed to remain dry and only have water in it in the event of a fire. The installed pre-action system developed pinhole leaks due to what appeared to be galvanic corrosion. An in-situ epoxy lining technique was used to stop the corrosion and restore the integrity of the fire suppression system piping. The work included lining of all interior pre-action piping mains, risers, branch laterals and service piping to individual sprinkler head locations, installing new ½” sprinkler heads on the preaction system followed by recertification of the pre-action system. This presentation describes the in-place epoxy lining process and presents before and after photographs of the coated system used to eliminate the pin hole leak problem.