To meet future demands in Collier County, a membrane treatment plant was designed that would be capable of treating multiple and changing sources of water to meet new water demands. While higher in initial capital costs than lime softening, the benefits of membrane treatment include better potable water quality (exceeding promulgated Federal and State standards by a considerable margin) and longer life of the facility because of its ability to treat different quality waters and multiple sources at one time. This is important because the County wanted to be able to take advantage of additional water availability in the existing wellfield, without limiting future utilization of the facility as would lime softening treatment. This facility can treat both freshwater and saline water at the same time using divided piping systems designed into the plant. Conversion to full reverse osmosis treatment in the future can be accomplished by simply changing the membranes and adding a pump stage. The concept behind this design addresses use of current membrane technology for solving future changes in regulations, changing water sources, changing water quality and flexibility in operations.