Take a dive into urban water use

Do you know where your water comes from? Or what happens to water after it goes down the drain? In urban areas, do you think we will have easy access to water forever? For many people, it’s likely that we go through the motions of everyday life without worrying about having access to water in our homes and businesses. So why question a resource that seems so reliable? 

Securing a reliable supply of water for all citizens is a complex task, despite it being readily available to many Americans. Water usage varies widely across regions and is heavily influenced by the strength of local infrastructure. For example, a resident in Mali, Africa may use just 3 gallons of water per day due to lack of access, while the average Arizona resident uses an estimated 146 gallons per day, according to the Arizona Department of Water Resources. Cities like Phoenix, Arizona, which are growing rapidly, must diversify their water resources to meet the needs of their residents. In addition to providing water for households, cities also use water for a wide range of purposes such as irrigation, industrial use, maintaining public spaces, and powering air conditioning. When we consider all the ways we use water and the number of people and facilities relying on it, it becomes clear that demand is quite high.

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Center for Disease Control and Prevention

In addition to our current standings, according to the United Nations Population Division, there are currently 3.6 billion people living in urban areas, and that number is expected to grow to 6.8 billion by 2050. With around 68% of the global population living in urban areas, there is going to be an ever-increasing demand for freshwater resources in order to account for urban water use. Taking into account the risk of droughts and regions with low precipitation, our seemingly abundant resource might be at risk without sustainable and regenerative water practices. On top of these statistics, a poll conducted by The Nature Conservancy showed that more than ¾ of Americans could not identify where their water comes from. So why is public knowledge of urban water use so low when water is so important?

Today, we hope to dive deeper into the topics of urban water resources, infrastructure, and systems. Our focus will cover the water supply in Arizona with the hope to inspire all urban dwellers that water conservation is key in population-dense areas, and there is room for improvement in just about every city across the globe. Why would we settle for anything less on a resource we all need to survive? Starting with where exactly our water comes from, we’ll analyze current systems and conservation efforts Arizona is implementing in order to keep this important resource available for many generations to come.

The desert’s most precious resource

To start with, it’s necessary to address why urban water infrastructure is so important. Having reliable and regulated water infrastructure in urban areas is crucial, as it primarily provides a safe and reliable source of drinking water. Unfortunately, this is not the case for every country. According to the World Health Organization,  it is estimated that 1 in 10 people (785 million people in total) still lack basic water services. Water services and infrastructure is essential for maintaining public health and preventing the spread of waterborne diseases, as it ensures the proper treatment and disposal of wastewater. Without proper treatment, wastewater can contaminate surface water and groundwater, leading to environmental degradation and public health concerns. Urban water infrastructure also plays a critical role in managing stormwater runoff. This helps reduce the risk of flooding and erosion, which can cause damage to property and natural environments as well as pollute local waterways. Overall, urban water infrastructure is essential for maintaining the health and quality of life of city residents, as well as protecting the environment. 

When addressing water in a desert city like Phoenix, the sources and management of water require thorough planning and resilient management. In the 20th century, Arizona received most of its water supply from groundwater. This system had apparent faults, as state leaders recognized that a healthy water supply needed a diverse portfolio of sources. The Arizona Department of Water Resources now breaks down Arizona’s water supply into four sources; Colorado River water, reclaimed water, in-state river water, and groundwater.

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Arizona Department of Water Resources

At 36%, the Colorado River supplies a considerable amount of water to Arizonans, as well as to 6 other U.S. states. But how exactly did a non-local resource become such a big supplier? In 1973, the Central Arizona Project (CAP) began construction in order to account for a growing population. 20 years later, the 336-mile water system that supplies the Pima, Pinal, and Maricopa counties, which accounts for more than 80% of Arizona’s population, was completed. With pumping plants, tunnels that traverse under mountainous terrain, and dams that hold reservoirs throughout the state, the CAP provides reliable, renewable water supplied by the Colorado River. However, having water resources outside of the Colorado River is crucial for Arizona and many other states using Colorado River water, as “the river is overallocated, meaning that the total volume of water users are entitled to on paper each year nearly always exceeds the physical amount of water the system produces”, according to ASU Kyl Center for Water Policy. As we highlighted in our previous article Should a Drought Nudge us to Conserve Water in the Desert, “To put it bluntly; the demand for water from the Colorado River exceeds the supply”.

Another resource of water is reclaimed water. This resource is primarily used for agriculture, golf courses, toilets, parks, industrial cooling, or maintenance of wildlife areas, as it comes from highly treated wastewater from a treatment plant. The Recycled Water Program regulates the use of recycled water, where gray water is collected from our washing machines, bathtubs, showers, and sinks. This does not include sewage flow, which comes from the kitchen sink, dishwasher, or toilet, according to the Arizona Department of Environmental Quality. It is even possible for citizens to collect their own reclaimed water to be used for home gardening, composting, and irrigation, as long as the flow is less than 400 gallons per day. As gray water can contain fats, oils, grease, chemicals, and more, it is important for individuals to be aware of where their reclaimed water is coming from in their homes and what they plan on using it on. To see the management practices of using gray water at home, visit ADEQ’s Gray Water Information Page.

Groundwater is also an important water resource in Arizona’s portfolio, as it supplies 41% of all water use in the state. Groundwater is sourced from springs and wells, and supplies flow for rivers as it seeps through the ground. This resource is rechargeable, as rainfall, streamflow, or melting snow sinks into the ground and replenishes the aquifer, but it is important to note the rate at which water is recharged into the ground. As the majority of Arizona is an arid or semi-arid climate, the state can see as little as 4 inches of annual precipitation in the southwest, resulting in humans taking more groundwater than is replenished each year. According to Audubon Arizona Groundwater, aquifers in Arizona took thousands of years to accumulate ample water supply, and if not managed sustainably, can take just decades to deplete.

Finally, we have in-state rivers, also known as the surface water we received from lakes, rivers, and streams. Sitting at 18% of our water supply, this resource is one that can vary from year to year, season to season, and place to place. The reservoirs and delivery systems located throughout the state are also important resources and landmarks of Arizona, making up the many man-made lakes and dams that citizens often visit for recreational purposes. The most notable major reservoir storage systems are on the Salt, Verde, Gila, and Agua Fria Rivers. With the Salt River Project being the primary management of these resources, they claim that dams located on these reservoirs also provide clean energy, flood control, and a steady water supply to the Valley. The seven reservoirs managed by SRP are also a supplier of aquifer recharging, where underground water storage is maintained by the reservoirs.

Following the flow

With the supply from these four resources being established, the water is then divided into three different uses; municipal, agricultural, and industrial use.

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Arizona Department of Water Resources

The majority of our water supply going to agricultural use may be surprising given the hot and dry region, but according to the Arizona Department of Agriculture, agriculture provides $23.3 billion to Arizona’s economy. The state’s climate also allows for year-round growing of hundreds of types of crops due to warmer winters, where 90% of the country’s winter vegetables are grown in Yuma, Arizona, staking the city’s name as “The Winter Salad Bowl Capital”.  In addition, 18,475 farmers and ranchers operating in the state are indigenous, which make up 57% of Arizona’s agricultural operations. The impact of indigenous peoples in agriculture results in $86.7 million in direct sales and operations of over 20.6 million acres in the state. With agricultural use having such a big footprint in our economy, high water use is nearly inevitable but has since been reduced from 90% to 72% since the 1950s due to improved water-use practices and conservation techniques. Agricultural water use has its limits, however, as each farm is assigned a maximum annual groundwater allotment and cannot exceed irrigation losses higher than 10%.

Municipal water use is the area in which citizens receive their water supply. To ensure municipal use is distributed equitably and sustainably, there are mandatory water conservation requirements that the sector must comply with, according to the Arizona Department of Water Resources. Large municipal water suppliers, for example, must participate in the Gallons Per-Capita Per Day (GPCD) program, or the Modified Non-Per Capita Conservation Program. This allows municipal water use to be documented, recorded, and adjusted if there are any issues with the supply. The municipal providers must also ensure that losses, usually from leaks, do not exceed 10% annually. While citizens are provided with water from suppliers, this is also the sector in which we have the most power to determine just how much water we conserve.

While industrial water use is the lowest user at just 6%, regulations are required in order to conserve water in our dry region. Industrial water supplies must ensure allotment-based requirements are met before supplying to turf facilities, dairy farms, and feedlots. Industries such as mines, cooling towers, sand and gravel operations, large-scale power plants, and new large landscape users must follow best management practices and design limitations in order to be considered for industrial water supply. 

Soaking up the conservation solutions

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Photo by Tom Gainor on Unsplash

Fortunately, cities and water suppliers are not standing idly by when it comes to water conservation. Susan Craig, Program Director for the Global Institute of Sustainability and Innovation at ASU’s Global Futures Laboratory, mentions water suppliers want to save water just as much as we do, if not more. There are many solutions currently being considered in Arizona, as the Kyl Center for Water Policy shows several projects ranging from ocean and groundwater desalination to dam modification. In an interview with Susan Craig, we review some of the major water goals and initiatives in Arizona from the perspective of an Arizona water expert. 

Check out this episode of The Green Scene here!

Phoenix, Arizona has implemented several measures to promote water conservation from a municipal perspective. Some of the initiatives and programs put in place include:

  • Water conservation rebates and incentives: Each municipality in Arizona offers its own conservation programs, many of which include rebates. To see what is available in your city or town, check out AMWUA’s Rebates and Resources Page.
  • Water conservation education: The city provides educational resources and programs to help residents learn about water conservation in their homes and businesses, and how to reduce their water usage.
  • Water conservation ordinances: Phoenix has implemented a number of ordinances and regulations to promote water conservation, such as requiring new developments to meet certain water-efficient standards (as mentioned above with the industrial and agricultural water supply).

Overall, these efforts have helped Phoenix reduce its water usage and better manage its water resources. Of course, with such a massive infrastructure including water providers bringing water to our homes, new infrastructure takes serious investment, both in money and time. In such a large state, water can go through quite the journey while moving through infrastructure, sometimes traveling 150 miles through SRP’s system just to reach our faucet. With ongoing projects and new legislation highlighted in our podcast with Susan, the importance of getting stakeholders and residents to get a good grasp on the importance of water conservation and efficiency is crucial. There are a number of ongoing projects outside of municipal water use as well, which are highlighted in the City of Phoenix Water Stewardship Goals, including sustainable ground and wastewater management, water infrastructure innovation, and the 100-year supply resiliency plan.

Doing your part in water stewardship

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Photo by Markus Spiske on Unsplash

The question remains; Should urban water users step up their conservation efforts and will it help offset water losses created by shortages? While many components of urban water infrastructure may seem out of the hands of the public, urban citizens certainly have a role to play in water conservation. In terms of the Colorado River specifically, only 16% of use goes to municipal users, but reductions in water use will “enable water providers to stretch out available supplies to serve more people and businesses”, according to the Kyl Center for Water Policy, “Because 90% of the water used indoors is reclaimed and reused, reductions in water used for outdoor landscaping provides the biggest benefits.” In a Cronkite News interview with Kyl Center for Water Policy’s Sarah Porter, she claims, “If everybody in Phoenix saved a gallon of water a week by not rinsing out containers, it would not help the problem.” She emphasizes that these efforts are great to promote water stewardship and to be more conscious of our consumption, but they are not the solution. The solution lies in the reduction of outdoor use. This includes water used for golf courses, private and public grass lawns, swimming pools, and irrigation for gardening.

 Also mentioned in our interview with Susan Craig, since outdoor water use is the most significant sector in which we need to reform if we wish to see bigger changes in municipal water conservation, this is where citizens can make a difference. Whether you are using your voice to encourage your city to make changes, or are simply switching water-use practices in your own home, here are a few tips to save as much as you can:

  • Encourage city planners or your HOA to implement drought-resistant landscaping in public parks and other green spaces.
  • Use drought-resistant plants in landscaping projects
  • Try out a new way of gardening, such as agroforestry or vertical farming, which can increase water efficiency and retain water.
  • Install water-efficient irrigation systems, such as drip irrigation or sprinkler systems that use sensors to only water when necessary.
  • Encourage the use of rain barrels and other water-saving technologies for residential gardens.
  • Encourage local governments to implement water-saving regulations and incentives, such as prohibiting watering during certain times of the day or offering rebates for residents who install water-efficient appliances.
  • Educate neighbors about water conservation through public campaigns and outreach programs.
  • Report any leaks in the city’s water infrastructure to The City of Phoenix Report Form (or search online for your city’s leakage report number) to prevent wasted water.
  • Consider using reclaimed or greywater for irrigation and other non-potable uses.
  • Encourage city planners or your HOA to use permeable pavement in new construction projects to allow water to infiltrate back into the ground rather than running off into storm drains.
  • Consider implementing water conservation pricing programs to encourage water-saving behavior.

As urban residents, it is important to have some general knowledge of where your water comes from, what happens after you use it, and what your city is doing to encourage water conservation. As urban populations continue to grow, cities must account for the growing demand for safe and reliable water. Having this knowledge of urban water infrastructure and implementing the practices of sustainable water use will ensure water remains to be an abundant resource for generations to come. Thank you for doing your part in water stewardship!

Helpful resources

Supplied by The City of Phoenix, Arizona Department of Water Resources, and the Kyl Center for Water Policy: