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Current shortage level: Tier 1

Moving to Tier 2A in January 2023

Shortage on the Colorado River does not mean a shortage at your tap.

Aerial View of Curved River

The Colorado River is an extremely important water source for the Western United States. Water from this system supports agriculture, industries, and millions of people across the region. 

Drought, climate change, and unsustainable allocations of Colorado River water have reduced water availability across the Colorado River Basin, and particularly in Arizona due to the current legal framework that governs River water rights. 

Because this river system is so important, the Bureau of Reclamation (Reclamation) monitors movements of water into and out of the system very closely and conducts regular hydrological modelling that forecasts future water supplies.


Reclamation completes a 24-month study every month and the August 24-month study determines how water supplies will be managed for the following year. A water shortage for the States of Arizona, California, and Nevada is determined based on the water levels in Lake Mead.

The image below shows how shortage is determined based on Lake Mead. 

New Tier 2a graph CAP.PNG

In 2021, the results of the August 24 month study initiated the first ever Tier 1 water shortage for 2022. The Tier 1 shortage decreased Arizona’s access to Colorado River Water by 512,000 acre-feet. This water reduction most heavily impacted central Arizona agricultural users. 

The 2022 August 24 month study showed elevation levels in Lake Mead below 1,050' resulting in a Tier 2A shortage starting in 2023. This shortage level reduces Arizona’s water supply by an additional 80,000 acre-feet beyond the Tier 1 reductions.

Lake mead elevation.PNG

Reclamation continues to conduct hydrologic modelling scenarios for the Colorado River system and some are showing higher possibilities for storage lakes (Lake Mead and Lake Powell) to decline to a point called ‘dead pool’ where no more water can be released for users.

This situation is serious and there will be long term impacts from ongoing Colorado River shortages in Arizona. However, it is important to recognize that there is no shortage at the tap. While we have enough water to use, we don't have enough to waste and that is why water conservation remains critical.  




AZ Water Allocation

  • Tier 0 Shortage 2020-2021 - reduced by 192,000AF 

  • Tier 1 shortage 2022 -  reduced by additional 320,000AF 

  • Tier 2A shortage 2023 - reduced by additional 80,000AF

Total reduction in 2023: 592,000AF of total 2.8million AF allocation 


Arizona has known for many years that a shortage could occur on the Colorado River. To prepare, water utilities have invested in infrastructure, water supplies, underground water storage, and conservation programs. As a result of our collective good habits, the state’s policy on how growth can occur, and planning we have been able to ensure water resources will be available for at least the next 100 years.

Global Water Resources has been committed to using water wisely since our creation. We use Total Water Management to ensure a sustainable future. We manage the entire water cycle, conserving water by using the right water for the right use.


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We live in the desert and understand the value of water. Water conservation helps to support our way of life in the desert.

Arizonans’ commitment to conservation and using water wisely has helped us to avoid drastic water saving measures like water restrictions during this time of prolonged drought.

Together we can ensure a sustainable future for Arizona by continuing our efforts to conserve and use water wisely.

Visit our conservation and education page to learn more about ways you can conserve inside and outside your home.


Global Water Resources wants to help you stay informed. You can sign up for our new water resources and conservation e-newsletter here

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