Fresh Water The BorderTransportationSystem will be pumping in salt water from the Gulf of Mexico and from the Pacific Ocean, as well as fresh water from rivers, lakes, and other sources along the route.  This Fresh Water will be purified or generated from the salt water via several desalination plants, and then piped to the locations that need the water. Index of ... Plumbing- Wikipedia Standards for materials used in plumbing systems Water Supply and Distribution Water Supply and Distribution - color codes