We are building a new home in a community that has some areas of high manganese in the water system. Some local plumbers are discouraging the use of cpvc pipes because they claim it causes a black residue to build up on the inside of the pipes over time. This black residue then leaches out and can be visible on the shower head, sink spray nozzle and other areas. They also say there is a distinct taste to the water, especially if the system has sat idle for a week or longer. Does anyone have any info on this subject. We are starting our plumbing in the next few days and would appreciate any help.