Performed leak detection and manifold tracing to determine which line was leaking. Found that the line leaking was the 3/4” copper on hot side of system that fed from behind downstairs master shower and came up behind secondary downstairs bathroom vanity. Recommend performing re route of this line to address leak. While I had the 3/4” manifold open exposed behind master shower I also saw that the 3/4” copper line coming from water heater over behind master shower was in poor condition as well. It would be a good idea to perform re route on this line as well while performing re route of the line that is leaking. It wouldn’t be much more work. Will submit an estimate for this work. While performing leak detection I noticed customer had two toilets that where continuously running. Recommend replacing of fill valves for both toilets