Discover What Happens If the Hoover Dam Ever Breaks

Written by Kyle Glatz
Updated: July 17, 2023
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The Hoover Dam is one of the largest dams in the United States. The dam measures 726 feet high, 1,244 feet long, and 600 feet thick at its greatest width. This massive concrete structure impounds the Colorado River, creating the largest artificial lake in the entire country, Lake Mead. This structure has stood since 1936, and it shows no signs of failure. Still, what happens if the Hoover Dam ever breaks?

Take a look at several problems that would emerge if the dam ever broke, including the immediate flooding that it would create.

Where is the Hoover Dam?

Las Vegas and Lake Mead, political map. Vegas, most populous city in Nevada, known primarily for its gambling and entertainment, left of Lake Mead, a reservoir formed by Hoover Dam on Colorado River.

The Hoover Dam straddles the border between Nevada and Arizona.

©Peter Hermes Furian/

Before considering what happens if the dam were to break, we must know where it is located. The Hoover Dam spans the border of Nevada and Arizona at the Colorado River. Specifically, one part of the dam is located in Clark County, Nevada, a southeastern county in the state. The other part is found in Mohave County, Arizona, an area located in the northwest of Arizona.

Like the Hoover Dam, Lake Mead is also in both Nevada and Arizona. This man-made lake is incredibly important to the region. The water from this lake provides water for Arizona, Nevada, California, and even parts of Mexico. Roughly 25 million people use water from this lake for drinking, plumbing, and irrigation.

Lake Mead has suffered from significant droughts in recent years, especially during 2021 and 2022. Still, the water levels were high enough to support people in the region. If the Hoover Dam ever breaks, that water supply would become unavailable, and immense suffering would strike the region.

What Happens if the Hoover Dam Ever Breaks?

colorado river

The flood of water from Lake Mead would be massive.

©Beth Ruggiero-York/

If the Hoover Dam ever breaks, the entire region downriver would suffer from immense flooding, a loss of available water for consumption and irrigation would create a humanitarian crisis, and the region would lose access to some power in the short term.

Fortunately, no signs of structural failures exist in the Hoover Dam, and everyone hopes that it stays that way. Take a look at how each of the aforementioned problems would look.

Flooding in the Region

Flood, Accidents and Disasters, Natural Disaster, Rescue, Assistance

Flood waters would inundate cities and towns along the banks of the river.

© Bruxelle

The first thing that would happen during a Hoover Dam failure would be an immense flood. At its full capacity, Lake Mead has 28,945,000 acre-feet of water. Every acre-foot is enough to cover one acre of land in one foot of water. Even if half of that water rushed out, it could cover an area about the size of West Virginia, a state with 15,507,046 acres of area. It’s true that it probably would not cover that much land, but the potential for flooding would be unlike any witnessed in the country before.

That is an inconceivably large amount of water that would rush downriver. When all that water comes flowing through a breach in the dam, many towns and cities would be flooded along the flow of the Colorado River.

If the Hoover Dam ever breaks, it would also wreck many dams downriver. The rushing water from Lake Mead would overwhelm the Davis Dam located 67 miles downstream, overtopping and possibly destroying the structure. There would be no way to stop all that water from moving as it continued south.

The flood of water would inundate towns like Laughlin. The Fort Mojave Reservation would also experience significant flooding and damage. Homes and buildings would become uninhabitable if the water did not destroy them outright. There is no way to tell how far the river banks would overflow during this scenario. However, the flood could reach as far south as Mexico.

By far, the flood would be the biggest immediate threat caused by a dam failure. However, it would not be the only problem.

Water Shortages

Corn plants wilting and dead in cornfield.

Farms throughout the region would lose access to water, leaving the crops to wilt.

© Gouin

Roughly 25 million people rely on the water contained in Lake Mead. After the Hoover Dam breaks, a great deal of that water would be lost. Certainly, the remaining supply of water would not be able to support all the people that rely upon it now.

While some areas would be suffering from a deluge of water, others would have almost none. Undoubtedly, people would have to relocate to have ongoing access to water. The lack of water would certainly lead to a major crisis.

Parts of southern Nevada, Arizona, and California obtain some of (if not most of) their water from Lake Mead and the Colorado River. Cities like Las Vegas, Boulder City, and Scottsdale would have severely limited water, affecting the lives of millions of people. The fountains in Las Vegas would dry up. People would be scrambling to have water to flush their toilets. Problems with sanitation would certainly arise.

The water from the Colorado River and Lake Mead is more than a local water supply for cities and towns. People also use it to bolster the agricultural industry in the area. As people struggle to obtain water to drink and use indoor plumbing, the farms in places like southern California would be left to wither.

Power Loss

Sign posted in a shop window: Shop closed, no electricity. Energy crisis, blackouts concept.

Blackouts could occur in the immediate aftermath of the dam failure.

©pamela ranya/

Currently, the Hoover Dam produces about 4 billion kilowatt-hours (kWh) of electricity through its hydroelectric power plant. The electricity from this structure is sent to California, Nevada, and Arizona. The power plant supplies electricity for roughly 1.3 million homes throughout those states.

What happens if the Hoover Dam ever breaks? Well, aside from the massive flood discussed above, the area would experience a significant loss of available electricity. Fortunately, other sources of electricity can pick up the slack. However, obtaining those fuels will not be as inexpensive as the hydropower generated by the dam.

Still, any loss of power amid such a huge disaster could be troublesome. However, the states near the Hoover Dam have other power supplies. In the worst case, they could seek transmissions from outside of the area. Yet, some of the infrastructure to carry power in the region could be knocked out by the flooding. If that is the case, then it does not matter how generous neighboring states may be.  

So, what happens if the Hoover Dam ever breaks? There would be a fair number of fatalities resulting from flooding and a lack of clean water. The agricultural industry would come to a screeching halt. The government would have to scramble to pick up the pieces and restore a sense of normalcy to the area. Immediate and long-lasting damages would occur in the region, and millions of people would essentially have to consider moving. Hopefully, such a disaster never comes to pass.  

The photo featured at the top of this post is © Pavone

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About the Author

Kyle Glatz is a writer at A-Z-Animals where his primary focus is on geography and mammals. Kyle has been writing for researching and writing about animals and numerous other topics for 10 years, and he holds a Bachelor's Degree in English and Education from Rowan University. A resident of New Jersey, Kyle enjoys reading, writing, and playing video games.

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