Charlotte Pipe and Foundry. ReUze new CPVC water piping system provides a practical, easy-to-install system for non-potable water uses inside residential buildings, a technology that can contribute up to 10 LEED points. The purple-colored pipe is marked with two lines of type clearly identifying the contents as non-potable water to ensure that water lines fit for human consumption are not crossed with non-potable water lines. www.charlottepipe.com.