<P> The installation of water pipes can be done using the following plastic and metal materials: </P> <Ul> <Li> polybutylene (PB) </Li> <Li> high density cross-linked polyethylene (PE - X) </Li> <Li> block copolymer of polypropylene (PP - B) </Li> <Li> the polypropylene copolymer (PP - H) </Li> <Li> random copolymer of polypropylene (random) (PP - R) </Li> <Li> Layer: cross-linked polyethylene, aluminum, high - density polyethylene (PE - X / Al / PE - HD) </Li> <Li> Layer: polyethylene crosslinked, aluminum, cross-linked polyethylene (PE - X / Al / PE - X) </Li> <Li> Layer copolymer of a random polypropylene, aluminum, polypropylene random copolymer (PP - R / Al / PP - R) </Li> <Li> polyvinyl chloride, chlorinated (PVC - C) </Li> <Li> polyvinyl chloride - not softened (only cold water) (PVC - U) </Li> </Ul> <Li> polybutylene (PB) </Li> <Li> high density cross-linked polyethylene (PE - X) </Li>

Which chemical is present in the ordinary tap water