For 110 years, Laramie, Wyoming, has obtained most of its municipal water from the Casper aquifer. As demands on the supply increased, the philosophies governing the management of the aquifer gradually changed. There has been an evolution through the following policies: (1) initial inflow-outflow safe yield concept, (2) simple conjunctive-use ground- and surface-water system, and (3) the beginnings of a conjunctive-use system that relies heavily on the storage properties of the aquifer. The evolution of management policy resulted from the press of changing demands on the system rather than innovative technical or scientific insights. Most technical advice solicited by the city in the past dealt with the immediate problem of how to augment the total supply. Through experience, the city became aware of the physical response and storage properties inherent in the aquifer, and by 1940 peak demands were being met by pumpage of water from storage. The city is currently weighing the advantages of purchasing additional surface-water rights, and has seriously asked its advisors if the aquifer can be managed solely as a peak-use reservoir. Under the proposed regime, large volumes of water would be withdrawn periodically from storage to meet summer and drought demands, while normal would be met from impounded surface water in the Laramie River.