H008
Where does the Colorado River's water go?
The river supplies 35 to 40 million people in cities from Los Angeles to Phoenix to Denver. All of those cities together use less of its water than the hay and other crops grown to feed cattle.
The users we picture aren't the biggest users. When people think about saving Colorado River water, they picture showers, lawns, and swimming pools in Las Vegas and Phoenix. But every city, business, and factory on the river, serving 35 to 40 million people, adds up to 18% of its water. Crops grown to feed cattle use 32%. Even the water that simply evaporates off the reservoirs, 11%, is more than half of what all those cities use.
When a total is being stretched, the most visible part is rarely the biggest part. Before deciding where to cut, whether a budget, a schedule, or a river, it's worth looking at how the whole is actually divided.
Try it somewhere else
A family wants to spend less. Everyone notices the daily coffee runs, but nobody looks at the car payment.
Which 10% cut would save more, and why do we notice the smaller one?
See the numbers
| Where the water goes | Million acre-feet per year | Share |
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What is an acre-foot?
An acre-foot is the water it takes to cover one acre 1 ft (0.3 m) deep. An acre is roughly the size of an American football field, so picture the whole field flooded up to your shins. That's about 326,000 gallons, or 1,233 cubic meters.
A typical home uses about half to a full acre-foot a year, indoors and outdoors combined. Western water is measured this way because farmers and water districts think in land: how many acres, watered how deep.
Does this mean farms are the problem?
Not by itself. These numbers show where the water goes, not whether that use is worthwhile. Hay feeds the cattle that become beef and dairy, farming supports many rural towns, and many farms hold some of the oldest water rights on the river. What the numbers do show is scale: a 10% cut in cattle-feed irrigation would save more water than a 15% cut across every city on the river.
That's why water negotiators spend so much time on farms, even though most public attention goes to cities.
What counts as “using” water?
These figures measure water consumed: water that evaporates, is taken up by plants, or is piped out of the basin and doesn't flow back to the river. Water that a city treats and returns downstream isn't counted. The numbers include water piped out of the basin to places such as Los Angeles, San Diego, and Denver, counted by what it's used for. They are 20-year averages (2000–2019) for the whole river, including the part used in Mexico.
Related exhibits
Sources: Richter, B. D., et al. (2024), “New water accounting reveals why the Colorado River no longer reaches the sea,” Communications Earth & Environment: average consumption of 19.3 million acre-feet a year (2000–2019), with 32% for cattle-feed crops, 52% for all irrigated agriculture, 18% for municipal, commercial, and industrial uses, 19% for riparian and wetland plants, and 11% for reservoir evaporation. Acre-foot volumes are those percentages applied to the 19.3 million total. Water Education Foundation, “What's an Acre-foot?”: 326,000 gallons per acre-foot and household use of 0.5–1 acre-foot a year. Number of people served: the U.S. Bureau of Reclamation cites about 40 million; the Pacific Institute estimates closer to 35 million (KJZZ, June 2026).