The pressing need for additional water supplies is driving utilities to seek alternatives to supplement or replace their historic water resources. The use of these alternative supplies can lead to changes in the aesthetic characteristics of the delivered water. Tucson Water has been increasing its use of an imported surface supply that differs significantly in TDS from the groundwater the community has traditionally relied on. The utility developed a public involvement program to engage customers in the decision of whether to accept rising TDS levels or to build a reverse osmosis facility to stabilize mineral levels. The "Decision H2O" program offers lessons to other utilities as they deal with customer responses to a changing water supply.