The color of PEX tubing does not affect what it can be used for. PEX plumbing tubing is manufactured in different colors only to simplify installation and make it easier and make it easy to identify your hot and cold lines in the future. Typically red tubing is used for hot lines and blue for cold lines, but theoretically you could do the opposite (which could get confusing!) Even with your lines color-coded, it is always a good idea to label the lines at the manifold so you also know which fixture they are going to in case you need to isolate an area for future repair.
White tubing provides another option for installers, for example if they want to buy a larger roll of one color to use for the entire system. In this type of installation it is even more important to clearly label the lines for future identification.
SupplyHouse.com has a large selection of PEX plumbing tubing made by manufacturers including Rifeng and AquaPEX.
