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Boulder Harbor at Lake Mead with cracked earth and abandoned boat

Water shortages

The Colorado River Basin is experiencing the worst drought in recorded history.

Since 2000, snowfall and runoff into the basin have been well below normal. These conditions have resulted in significant water level declines at major system reservoirs, including Lake Mead and Lake Powell.

The elevation of Lake Mead has dropped more than 150 feet since 2000. The Secretary of the Interior made the first-ever shortage declaration in 2021, which reduced the amount of water available to Nevada and other water users in 2022. A Tier 2 shortage declaration for 2023 operations further reduced the amount of water available to Nevada and Arizona. However, an exceptionally wet winter pushed Southern Nevada back into Tier 1 shortage for 2024. The risk of shortage remains high in future years.

What you can do to conserve

Current condition: Tier one water shortage

In January 2024, Lake Mead moved from Tier 2 to Tier 1 shortage, following a wet winter in 2023 that increased the reservoir's water levels. Despite the improved conditions in lake levels, Southern Nevada’s water supplies from the Colorado River at Lake Mead remain under shortage reductions. Under the Interim Guidelines and DCP, Southern Nevada's consumptive use will be reduced by 21,000 acre-feet. Colorado River water supplies for Arizona and Mexico are also under shortage reductions. (An acre-foot is equal to 325,851 gallons of water).

Nevada is not currently using its full Colorado River allocation, and near-term shortage declarations will not likely impact current customer use. By the end of 2022, Nevada's consumptive Colorado River water use was 224,000 acre-feet. This amount is below any Colorado River water supply reduction under existing rules.

 

What agreements are in place?

Federal, state and municipal water providers in the Colorado River Basin have worked together for more than a decade to slow the decline of Lake Mead water levels. The 2007 Interim Guidelines for the Coordinated Operations of Lakes Mead and Powell and the 2019 Lower Basin Drought Contingency Plan (DCP) are two agreements that benefit Nevada and other Colorado River water users.

Among other things, these agreements:

  • Keep more water in the river for the benefit of all water users and the environment.
  • Help slow Lake Mead water level declines to preserve critical reservoir elevations.
  • Allow for water banking in Lake Mead in the form of Intentionally Created Surplus.
  • Draw participation from new stakeholders, including California and Mexico.

Shortage Guidelines

The Bureau of Reclamation issued detailed guidelines in 2007 that mandate how Colorado River water stored in Lake Mead is managed during a declared shortage.

Under a shortage declaration, the amount of Colorado River water available to Nevada and Arizona is reduced. The Secretary of the Interior makes a shortage declaration for the following year when the U.S. Bureau of Reclamation's model projects Lake Mead to be at or below 1,075 feet on January 1 of the following year. The model is run annually in August.

Shortage amounts vary by state and are based on Lake Mead water levels. Nevada's shortage volume ranges from 13,000 to 20,000 AFY.

View the Shortage Guidelines

Drought Contingency Plan

Congress authorized implementation of the Lower Basin Drought Contingency Plan (DCP) in 2019. Under this agreement, Lower Basin States will begin making DCP contributions when the elevation of Lake Mead is projected to be at or below 1,090 feet.

Contribution amounts vary by state and are based on Lake Mead water levels. Nevada's DCP contribution ranges from 8,000 to 10,000 AFY. This volume of water is in addition to any mandatory reductions associated with a federally declared shortage. Nevada will receive credit for its DCP contributions. These credits can be recovered when Lake Mead is above 1,110 feet. Below this elevation, Nevada can access or borrow its credits, subject to certain restrictions.

View the Drought Contingency Plan

Nevada's combined shortage volume under these agreements ranges from 8,000 to 30,000 AFY, depending on Lake Mead’s water level. If at any time Lake Mead is projected to fall below an elevation of 1,030 feet, the Secretary of the Interior will consult with Lower Basin stakeholders to determine additional actions to protect Lake Mead from further declines.

In 2023, the U.S. Bureau of Reclamation's August 24-month study projected Lake Mead’s water level to be around 1,067 feet in January 2024 and drop by about 15 feet by August. In accordance with the DCP, the Secretary of the Interior and the Lower Basin States are actively engaged in consultation to establish additional plans and actions through 2026 to protect Lake Mead.

SNWA shortage and DCP obligations
Lake Mead water level Shortage amount DCP contribution Total
Above 1,090 feet 0 acre-feet per year 0 acre-feet per year 0 acre-feet per year
At or below 1,090 feet 0 acre-feet per year 8,000 acre-feet per year 8,000 acre-feet per year
At or below 1,075 feet 13,000 acre-feet per year 8,000 acre-feet per year 21,000 acre-feet per year
Below 1,050 feet 17,000 acre-feet per year 8,000 acre-feet per year 25,000 acre-feet per year
At or below 1,045 feet 17,000 acre-feet per year 10,000 acre-feet per year 27,000 acre-feet per year
Below 1,025 feet 20,000 acre-feet per year 10,000 acre-feet per year 30,000 acre-feet per year

Hoover Dam

Hoover Dam regulates Colorado River flows, provides water storage and produces hydroelectric power to Nevada, California and Arizona. The dam created Lake Mead, which stores Colorado River water for the lower basin states of Nevada, California, Arizona and the country of Mexico. Each of the Lower Basin states receives an annual allocation of Colorado River water as detailed in the Boulder Canyon Project Act.

Lake Mead can hold almost 9 trillion gallons of water. However, due to ongoing drought conditions and a hotter, drier climate, Lake Mead is at historic lows, and water levels are expected to decline even further. If Lake Mead falls below 895 feet in elevation, or dead pool, water cannot flow through Hoover Dam to California, Arizona and Mexico.

Photos from 1983, 2003 and 2023 show water level decline at the spillways at Hoover Dam

Climate change

Drought has become synonymous with the Colorado River over the last 24 years. This term can be misleading, implying a transient condition that will end. Evidence supports the fact that climate change is happening now and that it will have a lasting effect on the availability of Colorado River water supplies. 

Today, the best scientific projections available suggest that current Colorado River conditions will not only continue but worsen. Leading climate scientists warn of a permanent shift to a drier future, something known as “aridification.” In simple terms, aridification refers to drying conditions that result from warming, and it represents long-term change rather than seasonal variation or periodic droughts.

While climate change models project that warming trends will continue, the magnitude of change at a given location will depend in part on global mitigation efforts to reduce greenhouse gas emissions. Nevada's Clark County is projected to warm between 5 - 10 degrees by the end of the century. In Southern Nevada, the impacts of climate change are expected to be similar to that of drought. This includes extended durations of low Lake Mead elevations, water quality changes, possible reductions of Colorado River resources, and potential increases in water use to compensate for warmer and drier conditions.

The 2020 State of the Science Report confirms that temperature trends in the Colorado River Basin are increasing and precipitation, snowpack water volume and annual streamflow trends are decreasing.

Adaptive management

The Water Authority is responsible for anticipating future water demands and taking the steps necessary to meet them. Over the years, the agency has taken a number of adaptive management steps to reduce the impacts of drought and climate change on water supplies and facilities.

  • Through one of the nation’s most progressive and comprehensive water conservation programs, Southern Nevada has reduced its Colorado River consumption. The community used 33 billion gallons less water in 2022 than in 2002, despite adding more than 745,000 residents during that time.
  • The Water Authority has constructed a third drinking water intake and a low lake level pumping station at Lake Mead to ensure continued delivery of Colorado River water to Southern Nevada under low reservoir conditions.
  • Through compliance and sustainability efforts, the Water Authority seeks a balance between water resource use and environmental stewardship, including species habitat conservation and protection.
  • Through water banking efforts in Nevada, Arizona, California and in Lake Mead, the Authority has accrued more than 2.3 million acre-feet of water. This is more than 10 times Nevada's 2022 consumptive Colorado River water use. Like a savings account, water banking provides the Water Authority with the ability to store water for when it is needed.
A bar chart showing the 2022 Colorado River consumptive use and banked resources

Continued water conservation and adaptive management are ongoing priorities as our community responds to drought and climate change.

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