Water Efficiency

Sources

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Phoenix has three sources of water – surface water (rivers and lakes), groundwater pumped from wells, and reclaimed water. These sources are used for agriculture, and industrial cooling and landscaping. Our supplies are rarely in a location where most of the population can see them.

Here, you can learn about Phoenix’s water, where it is treated, and how we plan for customer’s needs.

• The Colorado River

  • Colorado River

    Up to 693 miles

  The Colorado River typically accounts for nearly half of the City’s water supply. It winds over 1,400 miles from Colorado to the Gulf of California in Mexico. The watershed covers approximately 244,000 square miles, including parts of Wyoming, Colorado, Utah, New Mexico, Nevada, California, Arizona and Mexico. The Colorado River has to meet the water needs for parts of these states and Mexico.

  Melting winter snows from the mountains of Colorado, Utah and Wyoming provide more than 85% of the river’s water. The amount of melting snow varies considerably year to year and prolonged drought - sometimes lasting decades – is not unusual. A rainy winter in Phoenix doesn't mean snow will melt into the Colorado River and fill Lakes Powell and Mead.

• Salt and Verde Rivers

  • Verde River

    Up to 128 miles

  • Salt River

    Up to 165 miles
  

  The Salt and Verde Rivers are another major water resource for Phoenix residents. More than a century ago, farmers in the Salt River Valley sought help from the federal government. The government built a series of dams and reservoirs along the Salt and Verde Rivers. These lands are now what we know as the Salt River Project. SRP now mostly provides water for urban uses.

  The rivers are fed by winter snows above the Mogollon Rim northeast of Phoenix. Winter weather systems, fires, and summer monsoons can impact the quantity and quality of this water resource.

• Hoover Dam and Lake Mead

  • Hoover Dam

    About 234 miles

  • Lake Mead

    About 234 miles

  Hoover Dam is an engineering wonder that has made it possible to harness the Colorado River. It helps provide water and energy to Arizona, Nevada, and southern California. Completed in 1935, the dam created Lake Mead, the largest man–made reservoir in the United States. The lake can store up to 9,299 trillion gallons of water. This represents the entire average flow of the river for two years.

  In 2010, after an eleven year drought, the lake’s level dropped to its lowest level since filled 75 years ago. However, heavy snowfall in the Rockies during winter 2011 provided enough water to raise the lake more than 13 feet.

• Lake Powell and Glen Canyon Dam

  • Lake Powell

    About 244 miles

  • Glen Canyon Dam

    About 244 miles
  

  Glen Canyon Dam creates scenic Lake Powell, the second largest reservoir on the Colorado River. The lake has capacity to hold 8,798 trillion gallons of water. The completion of the dam in 1966 nearly doubled storage capacity of Colorado River water. The combined capacity of Lakes Mead and Powell helps prepare for dry years. However, when lake levels drop due to a long drought, it can take a long time to refill them.

  The primary purpose of the dam is to generate electrical power to areas of western United States. The sale of 4.5 billion kilowatt hours of electricity help pay the original cost and to maintain the system.

• Roosevelt Lake and Dam

  • Roosevelt Lake & Dam

    About 56 miles
  

  Fifty-six miles northeast of Phoenix is Roosevelt Dam, the first federal project created to supply water for the Valley. The dam was completed in 1911 and created Roosevelt Lake. The lake can store more than 539 trillion gallons of water and is the largest lake on the Salt River system. There are also a series of small lakes closer to the Valley well known for recreation.

  The dam and lake are very important for managing the Salt River. They provide a consistent supply of water to the Valley. However, compared to the Colorado River System, the ability to store water on the Salt and Verde Rivers is small. It is not unusual to find water flowing in the Salt River through Phoenix during wet winters. This is when the lakes of the Salt and Verde Rivers are full. In 1996, the dam was raised to improve flood control and increase storage.

• Central Arizona Project

  • CAP Canal

    Starts 136 miles
  

  In 1963, the Supreme Court settled a long running dispute between Arizona and California. The Court decided Arizona has a lower priority to Colorado River water than California. If there is a severe shortage, Arizona’s supply from the Colorado River may be reduced. However, the Court ruling allowed for construction of the Central Arizona Project. The CAP was authorized in 1968, to bring Colorado River Water to central and southern Arizona for the first time.

  Construction of the Central Arizona Project began in 1973. The canal was completed to Phoenix in 1986 and to Tucson in 1992. The canal is designed to carry 3,000 cubic feet of water per second. Because the Central Arizona Project transports Colorado River water uphill for its entire length, it is the largest power user in Arizona.

Wet and Dry Cycle

1. 1200 – Now

   During the last several centuries in the Southwest, there have been periods of heavy rainfall and snow causing severe flooding. There have also been long periods of drought. Studies at the University of Arizona’s Laboratory of Tree Ring Research helped in understanding the climate's effect on desert communities.

2. 1200 – 1300

   Around 1275, studies show that there was a ‘great drought’ in the Southwest. Droughts can cause disease and pest infestation to trees and wildlife. An example is the recent infestation of the Pine Bark Beetle in our forests. The beetle has killed more than 50 percent of trees in some areas.

3. 1400 – 1500

   The Hohokam community is believed to have been as large as 24,000 to 50,000 people. They were a population that would need a constant supply of water for crops and home in our arid desert. Sometime around 1450 AD, the people abandoned the greater Phoenix area. Tree ring studies show that there was a great flood at that time. The flood may have destroyed the canal system that made living in the desert possible.

4. 1500 – 1600

   Tree ring studies showed much of the southwestern United States and Mexico experienced a severe drought in the late 1500s. The drought was unlike any dating back as far as 1200 AD. Droughts of this type impact agriculture and natural resources. They may have even led to war to gain water sources to sustain a community in Mexico.

5. 1900 – 1922

   The Colorado River Compact determined states' water usage. The compact was based on average river flows at Lee’s Ferry for a period before 1922. It has since been established through tree ring research that the river was over-allocated by about 3-million acre feet. This was due to higher-than-average flows during that time.

6. 1950 – 1957

   A severe drought for the Southwestern U.S. began in 1950 and lasted until 1957. This drought was characterized by both high temperatures and low rainfall. The impact on agriculture was especially harsh for cattle ranching and reduced crop yields by as much as 50%.

Water Treatment Plants

Phoenix has five water treatment plants delivering a safe and reliable water supply to your home. The Central Arizona Project delivers Colorado River water to the Union Hills and Lake Pleasant Water Treatment Plants. These plants are in north Phoenix. Three plants in central Phoenix treat Salt River Project water for customers ‘on project’. During plant maintenance or drought, Central Arizona Project water can be moved to all plants for delivery.

More than 6,000 miles of interconnected water pipes delivers about 264 million gallons of water daily to Phoenix customers. Deliveries are adjusted monthly to meet customer demands. Deliveries vary depending on a variety of issues including weather, tourism, and other consumer needs.

Waste Water Treatment Plants

Wastewater is collected from Phoenix homes and businesses through more than 4,600 miles of pipe. It is sent to the City’s three wastewater treatment plants. Once treated, most of the reclaimed water is reused for cooling at Palo Verde Nuclear Generating Station. It also is used for irrigating farmland and turf, and at the Tres Rios wetlands. Using reclaimed water at these locations preserves our drinking water supply.