Allocation of water resources has been and continues to be a very significant topic in the United States. Although historically considered a concern primarily for western states, eastern water supplies have become increasingly erratic due to overuse, short-term droughts, and potential long-term climatic changes. These factors have been aggravated by development patterns, groundwater pollution and saltwater intrusion. Interestingly, epic western water wars have recently come east and there is no end in sight. This session will discuss the history of water quantity regulation in both the western and eastern portions of the United States, from English common law through increasing statutory regulation. It will also provide insight into the directions both eastern and western states have taken and likely will continue to take in confronting ever-increasing shortages of water.