No, they do not. While it’s technically true that 40 million people across seven states and Mexico have water systems that are supplied in part by the Colorado River, it’s misleading to imply that 40 million people depend on the Colorado River entirely. But the statement – which was taken out of context, has been repeated so often by the media and others that it’s now widely-accepted as a fact. It originated from a Bureau of Reclamation report that actually says, “Although agricultural uses depend on 70 percent of Colorado River water, between 35 and 40 million people rely on the same water for some, if not all, of their municipal needs”.1
Top three reasons why the shortened “40 million” phrase is misleading
1. Agriculture consumes the vast majority of the water, not individuals
The phrase implies that 40 million people rely on the river primarily for drinking, bathing, and basic survival. In reality, agricultural irrigation consumes roughly 75% to 80% of the river’s water. A massive portion of that goes specifically toward water-intensive cattle feed crops like alfalfa and hay. Domestic, household use accounts for only about 10% to 13% of the total supply. The narrative of “40 million thirsty citizens” masks the fact that the crisis is fundamentally an agricultural management problem rather than a residential population crisis.
2. Major urban areas only use the river as a fractional supplement
Many of the 40 million people counted in this statistic live in large coastal or metropolitan cities—such as Los Angeles, San Diego, Denver, and Phoenix—that do not rely solely on the Colorado River. These cities utilize a diversified portfolio of water sources, including local groundwater, northern state aqueducts, state-wide recycling systems, and other local river basins. Saying they “depend” on the Colorado River implies total reliance, when it often provides only a fraction of their municipal supply.
3. Aggressive water recycling and conservation significantly reduce our “dependence”
Using the word “depend” creates a fatalistic narrative that if the river’s flow drops, 40 million people will run out of water. In practice, many of the urban centers counted in the 40 million figure are highly resilient due to aggressive wastewater recycling and conservation efforts. For example, Las Vegas and the state of Nevada recycle nearly 85% of their treated wastewater back into Lake Mead. Because these cities reuse the same water multiple times, their actual net depletion of the river is much lower than their gross population would suggest.