Tucson and Pima County officials announced drought alerts Wednesday as Arizona faces nearly two decades of drought conditions. The alerts come amid projections that Lake Mead’s water level could drop below critical thresholds next year, potentially triggering mandatory water restrictions due to reduced Colorado River supplies, according to the U.S. Drought Monitor and local water authorities.
Lake Mead’s water level is projected to fall below 1,045 feet above sea level next year, a threshold that could trigger mandatory water restrictions for Arizona, officials said. The U.S. Drought Monitor and local water authorities warn that this decline would activate a Tier 1 shortage designation for the Colorado River Basin in 2025.
This shortage would reduce Arizona’s water allocation from the Colorado River by 512,000 acre-feet, representing about 30% of the Central Arizona Project’s (CAP) normal supply and 18% of the state’s total Colorado River water supply, according to CAP records.
Pima County, which has a population of approximately 564,875 people affected by drought conditions, remains under severe stress with no change in drought-affected population since last week but a 7% increase compared to last month, according to the U.S. Drought Monitor. The county faces the possibility of entering D4 Exceptional Drought conditions, which involve widespread crop and pasture losses as well as significant water shortages, local officials said. The Arizona Department of Water Resources’ Community Water Systems Data Dashboard is being used by Pima County for ongoing drought planning and response efforts.
Tucson, located within Pima County, is currently in Tier 2 of its Drought Preparedness and Response Plan due to the anticipated drop in Lake Mead’s water level. This plan includes four tiers of drought response that outline specific measures for city operations and community water use, officials said. Tucson Water District (TWD) manages a 149,000 acre-foot groundwater system sourced from CAP water recharged into the local aquifer at Avra Valley. Records show that since CAP’s construction, Tucson has stored approximately one-third of its annual water supply underground, using only about 100,000 acre-feet per year to meet community demands.
Despite the ongoing drought, Tucson has nearly five years’ worth of Colorado River water stored underground, exceeding current demand, Tucson Water officials said. In 2023, the city agreed with other regional water users to leave roughly 30,000 acre-feet of Colorado River water in Lake Mead to help slow the reservoir’s decline, according to Tucson Water District representatives. This stored water is available for delivery to Tucson customers during drought periods, officials confirmed.
Water conservation efforts have played a significant role in managing the region’s water resources. Tucson Water customers have reduced total water use over the past 20 years despite population growth, according to city records. The city conducts regular water audits, replaces inefficient toilets, repairs irrigation systems, and improves cooling tower efficiency at municipal facilities. Remaining efficiency upgrades at high-water-use facilities are scheduled for completion by the end of 2023, officials said. Additionally, Tucson recycles wastewater for non-potable uses such as irrigation, further conserving potable water supplies.
Robert Glennon, a water policy advisor to Pima County and law professor at the University of Arizona, emphasized the severity of the situation, stating, “These figures could result in hundreds of thousands of acre-feet less for Arizona; it’s a math problem and the numbers don’t add up.” Glennon’s statement reflects concerns over the long-term sustainability of water supplies given the persistent drought conditions.
The Colorado River Basin’s Tier 1 shortage designation for 2025 will predominantly impact CAP water users, according to CAP officials. The reduction of 512,000 acre-feet translates to just under 8% of Arizona’s total water use statewide. An acre-foot, which equals 325,851 gallons, typically supplies water for four Tucson households for one year, Tucson Water representatives noted.
Tucson updates its long-range water management strategy every decade, with the current plan titled One Water 2100. This plan integrates groundwater management, drought preparedness, and conservation initiatives to ensure sustainable water use for the community. Groundwater maps, including the Depth to Groundwater report, are used to monitor aquifer levels and guide resource planning.
The city’s Drought Preparedness and Response Plan requires all municipal departments to follow audit recommendations aimed at improving water efficiency and reducing waste. These measures not only conserve water but also save money and resources, officials said. Tucson Water’s Water Service Area Policy also guides adjustments in response to changes in Colorado River water availability.
Federal tracking through Drought.gov monitors the impacts of drought on water supply, public health, and agriculture in Pima County. The prolonged drought, which has lasted nearly 20 years, is attributed primarily to below-average inflows into the Colorado River and Lake Mead, which provide about 40% of Arizona’s water, according to water experts.
As drought conditions continue, local and regional authorities remain focused on implementing conservation measures and managing stored water supplies to mitigate the effects of potential shortages. The situation underscores the ongoing challenges faced by Arizona in balancing water demand with dwindling supply amid persistent drought.
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