Lake Mead and Lake Powell are both fed by the Colorado River. Combined, the two haven't held this little water since 1957. 

That 1957 comparison is more telling than is seems. Lake Powell didn't exist back then — construction on Glen Canyon Dam had only just begun in 1956, and the reservoir wouldn't start filling until 1963.

So in 1957, that "combined Mead and Powell" total was really just Lake Mead by itself. Since then, Powell added roughly 25 million acre-feet of storage capacity to the system — nearly doubling the total. 

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These reservoirs serve several vital functions: drinking water supply, power generation and economic and recreational support. All of these are at risk as water levels decline.

Lake Mead

Lake Mead, the country's largest reservoir, is located just east of Las Vegas along the Nevada–Arizona border. It began filling in 1935 following the construction of the Hoover Dam on the Colorado River.

Currently, the water level sits just below 1,040 feet. On Sept. 16, 2026, Lake Mead surpassed its previous record low from July 2022, and levels have generally declined this year.

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It’s a crucial supplier of drinking water to millions in the West. Over 40 million people rely on the Colorado River system for water. 

(MORE: The country's largest reservoir is running low, signaling a 'dire water supply situation’)

Hoover Dam generates hydroelectric power for Nevada, Arizona and California. As the lake has dropped, less water has moved through the turbines, and Hoover's power output has already fallen well below its capacity — down an estimated 40 to 50% from 2000 levels, when Lake Mead was full.

It also hosts approximately 8 million visitors annually, contributing $374 million to the regional economy and supporting roughly 4,000 jobs.

According to National Park Service data, visitors flock to these water bodies for various recreational activities, including boating, swimming, sailing, kayaking, and fishing.

Lake Powell

Lake Powell, the country's second-largest reservoir, is located on the Utah-Arizona border.

In August, it fell to its lowest water level since it was first filled in the 1960s. Right now, it’s just over 3,500 feet.

(MORE: Lake Powell hits record low, moving closer to shutting down Glen Canyon Dam)

Lake Powell is a vital power source, keeping the massive turbines inside Glen Canyon Dam spinning.

If the water level falls too low, it would cut off the primary, low-cost electricity source for roughly 5.8 million homes and businesses across seven states: Wyoming, Utah, Colorado, New Mexico, Arizona, Nevada and Nebraska.

Why the water levels are so low

A few factors are at play for the current state of affairs.

First, the crisis is driven by decades of overuse. Despite the water supply continuously dropping over the years, overall water consumption has not decreased to match.

Part of that overuse story is how much bigger the cities drawing on this water have gotten. 

Las Vegas had a population of roughly 64,000 in 1960; today, the metro area is home to about 2.5 million people. Phoenix grew from roughly 726,000 in its metro area in 1960 to nearly 5 million today.

Almost all of that growth happened during decades when the Colorado River reliably delivered more water than it does now — so today's demand is built for a river system that no longer shows up the way it used to.

Second, the region has been experiencing an extreme, historic drought all year.

According to the National Park Service, the region has endured exceptionally dry conditions since the 2000s, "coupled with the ongoing effects of climate change, reduced snowpack and low runoff conditions."

Snowpack is crucial for maintaining water levels in the Colorado River Basin, which feeds both lakes.

Snow accumulates at higher elevations and slowly melts over the warmer seasons, providing a consistent supply of water over time.

However, reduced snowpack combined with unseasonably warm weather earlier in the year caused water levels to decline even further in 2026.

The drought and El Niño’s role

Despite a particularly rough year for water levels so far, El Niño could offer some relief.

El Niño increases the likelihood of a wetter, more active Pacific storm track, bringing above-average rain and snow to much of the Southwest.

(MORE: The West’s best shot at snowpack recovery comes from El Niño)

However, a single good winter won't solve the larger issue. This megadrought has persisted for over 25 years — making it one of the driest multidecade stretches the region has seen in roughly 1,200 years.

While El Niño could help levels stabilize or slightly increase by next spring, it will not refill the reservoirs. Doing so would require years of consecutive, well-above-average snowpack—a level of sustained moisture that is neither forecasted nor expected anytime soon.

Content writer Ada Wood enjoys exploring the stories that science and climate teach us about our natural world and how it influences the way we live in it.