From The Denver Post (Bruce Finley):
The number of gallons per person used daily in Denver and other South Platte River basin cities decreased 13.6 percent between 2000 and 2008, to 178 gallons from 206 gallons. Water use in Colorado Springs and Arkansas River basin communities decreased during that time by 11.2 percent to 190 gallons, down from 214…
Water use rose to 256 gallons per person in the Colorado River basin, 332 in the Rio Grande, and 236 in the Dolores/San Juan, according to Colorado Water Conservation Board data…
The new Colorado Water Conservation Board data indicate wide variations in consumption statewide. Residents of Pitkin County, home of Aspen, used 1,851 gallons per person each day, the data show, as Elbert County folks used 111 gallons each. Water analysts attributed the decreasing water use in Front Range cities to conservation programs that create financial incentives. Denver Water, for example, pays customers up to $150 to replace a toilet, shower or washing machine with a newer, more efficient model.
More conservation coverage here.