Approximately 40 million people currently live in the Colorado River basin and depend on its water. Each of those people places a “demand” on the water in the basin. The average person in the Colorado River basin uses about 200 gallons of water per day – in kitchens, bathrooms, laundry rooms, and in their yards. Along the Front Range of Colorado, approximately 40% of all water is used for 3 months in the summer to keep lawns green; that percentage may be even higher in the desert landscapes of Arizona and southern California.

Human populations are expected to continue to grow in the Colorado River basin. Compared to population numbers in 2000, the U.S. Census Bureau expects an average of a 53% increase in population in the year 2030 in the Colorado River basin states. This new population growth will all require new and more water, and place even more demand on the Colorado River and its tributaries. Due to population growth, demand for water in the Colorado River basin has already outstripped supply – this trend is expected to continue in the future as water supplies decrease (due to drought and climate change), and population increases.