Desert plants and animals have adapted to Tucson's 12 inches of rainfall per year, and those of us who live here learn to adapt as well. We use our water for drinking, bathing, swimming, and cleaning things that attract desert dust.

Because it is rare, many of us are attracted to it. We learn to conserve it, and seek out local lakes and pools during the summer seasons.

Our local utilities conserve it as well and in the past have launched substantial marketing campaigns reminding Tucsonans when to water our plants and check for leaks in our indoor plumbing and outdoor irrigation systems.

Much of the water we use has traveled long distances. Some has been stored in the ground around us, and some has been recycled after we have used it.

The story of Tucson's water is a fascinating journey, shaped by the land, the climate, and the rivers and canals that make their way to our city.

 
Climate

Tucson has one of the best climates in the U.S. The city is known for its clear blue skies, low rainfall and wide-open deserts. It is a mecca for professional and amateur astronomers and those escaping the cold winter weather of the north and east. Those of us who live here can hike, bike and swim year-round.

In 2008 Tucson adopted the Framework for Advancing Sustainability, establishing a series of sustainability initiatives after the Tucson city council signed on to the Mayors Climate Protection Agreement which committed cities to reducing greenhouse gas emissions to 7% below 1990 levels.^[3],[5]

In 2011 Tucson prepared the Community Economic Security and Climate Action Analysis, an assessment of citywide climate change citywide and strategies for action.^[4]

On September 9, 2020 the Tucson City Council declared a climate emergency, and committed to developing and implementing a comprehensive 10-year Climate Action and Adaptation Plan. The declaration requires all city departments to align efforts with the Paris Agreement and the Green New Deal, and identify people-centered climate adaptation and mitigation strategies.^[1]

The Climate Emergency Declaration includes energy conservation measures, clean transportation, and water management, stormwater capture and ecosystem rehabilitation that removes non-native vegetation that stress the water system.^[1]

On March 7, 2023 the Tucson city council adopted a climate action plan entitled Tucson Resilient Together. The plan addresses five areas:

• governance and leadership to coordinate and implement the plan with community organizations, businesses and regional partners
• energy and actions to reduce city and community emissions and integrate renewable energy
• transportation to low- or zero-emission modes and land use changes to promote transit-oriented development
• community resilience and climate change adaptation
• resource recovery and management actions to reduce emissions from resource use and disposal and expansion of green infrastructure^[2]

In the winter the primary wind flow in Arizona is from the west or northwest from California and Nevada. As summer begins winds shift to a southerly or southeasterly direction. Moisture streams northward from the Pacific Ocean and the Gulf of Mexico, producing a change in moisture conditions.^[6]

The wind shift is caused by two events: northward movement from winter to summer of upper air subtropical high pressure cells called the Bermuda High and intense heating of the desert which creates rising air and surface low pressure in the Mohave desert. These events create strong southerly flow over Arizona which pushes moisture northward from Mexico.^[6]

The exact source region for the moisture of the Arizona monsoon is unknown but researchers have proposed the Gulf of Mexico or the Gulf of California as source regions.^[6]

Tucsonans frequently wait for the monsoons to arrive, but the correct term is monsoon thunderstorm. These storms are powered by intense surface heating and strong moisture flow into Arizona.^[6]

Before 2008, the monsoon's start date and duration were based on dew point average. The official Arizona monsoon start date was after the third consecutive day of dew points above 55⁰F and ended when it dropped. To reduce confusion and starting in 2008 the National Weather Service set the start date as June 15 and the end date on September 30.^[7]

Sources:

 
Santa Cruz River

The Santa Cruz rivershed is 8,200 square miles and was the foundation of early settlements for native populations.^[1] In 1200 BC, the Hohokam began using the Santa Cruz for irrigation, drinking water and fishing.^[2]

In 1691, Spaniards brought new crops and livestock. By the 1890s, the river began to disappear because settlers were depleting groundwater using pumps. In the late 1800s, the Santa Cruz was dammed to create Warner and Silver Lakes, and gardens and picnic areas were created along the river.^[2]

Cottonwood, willow, walnut and mesquite trees grew along the banks. By the 1950s, the river stopped flowing because of years of mismanagement urban expansion,^[2], drainage, diversion, channeling and cementing.^[1]

The Tucson Mission Garden, located in the Santa Cruz River flood plane, is located at the intersection of Mission Avenue and Melwood Lane, at the foot of Sentinel Peak, also known as A Mountain. It is the site of the ancient Tohono O'odham sacred village of S-cuk Son, pronounced Chuk Shon, and has been continuously cultivated for more than 4,100 years. It is managed by Friends of Tucson's Birthplace.^[6]

As a living Sonoran Desert agricultural museum of heritage fruit trees, traditional local heirloom crops and edible native plants it hosts Hohokam, O'odham, Spanish, Mexican and Chinese gardens, a medicinal garden, a granary and a chicken coop.^[6]

Environmentalists and researchers are reversing the damage.^[1] The Santa Cruz River Heritage Project adds up to 2.8 million gallons of treated recycled water, called reclaimed water, to the river every day, totalling about 3,150 acre feet per year. The water is added south of downtown near the center of Tucson, and will enable the river to flow all year, while facilitating vegetation growth, promoting wildlife and the possibility of new recreational opportunities.^[3]

A 980-foot pipeline, called an outfall, brings water from the reclaimed system to the river channel where it creates a a narrow stream of purified, reclaimed water within the larger river channel, where it percolates the ground and enters the aquifera body of permeable rock which can contain or transmit groundwater for later use. This project will help bring the river back to life.^[3]

In 1967, the Gila topminnow was placed on the U.S. endangered species list, and in 2020, 500 were reintroduced into the Santa Cruz. As of 2022, there were about 1,800 of the small fish in the river.^[7],[9]

On March 23, 2022, as part of a city, county, U of A, Arizona Game and Fish and U.S. Fish and Wildlife Service effort, about 600, 3-inch longfin dace, were released into the Santa Cruz in locations where Tucson and Pima County are using treated wastewater to restore natural habitat destroyed in the 20th century. The two species are expected to peacefully coexist, eating mosquito larvae and serving as food sources for kingfishers and herons.^[7],[8]

No one knows exactly which wildlife, insects and vegetation may return to the reclaimed part of the river,^[4] but the Heritage Project will help reconnect Tucson residents with the river that served as the foundation of our city.^[5]

The Wa:k Hikdan project began in May 1990, when the San Xavier District Council supported restoring part of the Santa Cruz. In 1996, the District was awarded an Arizona Water Protection Fund (AWPF) grant to finance the project. About 12 acres were selected, near the riverbank southwest of Martinez Hill in the northwest region of the District.^[10]

Through the 1982 Southern Arizona Water Rights Settlement Act (SAWRSA), the District was granted 50,000 acre-feet of Colorado River water delivered via CAP. SAWRSA also provided federal funds to build a pipeline to deliver CAP water to the San Xavier Cooperative Farm.^[10]

In 2000, the 5.6-mile-long CAP Link Pipeline was completed, connecting the CAP canal to the farm's original water distribution system. In 2002 workers planted native vegetation, including cottonwood, willow and mesquite. By 2023 the cottonwood and willow, and sycamore, ash and mesquite varieties brought this area of the river back to life.^[10]

^[10]

 
Rillito River

During the 20th century, that habitat disappeared due to the depletion of groundwater needed to support agriculture and a growing population. The river is now dry, flowing only ephemerally during monsoon season.^[1]

Riparian habitats are extremely important for native and endangered species. Their destruction decreases diversity and enables invasive, water-consuming species to thrive, straining already limited water supplies.^[1]

A major part of the Chuck Huckelberry Loop, a paved network of bike and walkways, connects the Rillito with the Cañada del Oro, Santa Cruz and Pantano River Parks with the Julian Wash and Harrison Road Greenway. The Loop extends through Pima County, Marana, Oro Valley, Tucson and South Tucson.^[2]

Sources:

 
Groundwater

The Tucson AMA includes two groundwater sub-basins, the Avra Valley sub-basin and the Upper Santa Cruz sub-basin and the Santa Cruz AMA, which was created in 1994. It is 3,866 square miles of Pima, Pinal and Santa Cruz counties, cities and towns of Tucson, South Tucson, Oro Valley, Marana, and Sahuarita, Pascua Yaqui Tribal lands, part of the Schuk Toak District, and the San Xavier District of the Tohono O`odham Nation.^[3]

The USGS found that in the past TAMA groundwater withdrawal rates resulted in net removal of water from groundwater storage and small water-level declines during the last several decades. Because of good water management these declines declines have stabilized or reversed since 2000 at most areas in Tucson Basin and Avra Valley have increased.^[1]

The water in our Tucson taps is a blend of recharged Colorado River water and groundwater from Tucson's Colorado River rechargereplenishing an aquifer by surface infiltration or by other natural or induced means facilities and recovery fields, known as clearwater. Tucson water recharges more water than it pumps, which means Tucson has a sustainable supply for the future. If there is an interruption to Central Arizona Project (CAP) canal deliveries, Tucson Water has a large underground supply at pumping sites.^[2]

 
Recreation and Lakes

• Agua Caliente Park, located just east of the city, is a 101-acre park with a warm spring and pond. There is evidence of human habitation dating back about 5,500 years. In 1873 a ranch and health resort was developed to promote the curative properties of the warm springs. In 1984 Roy Drachman donated more than $200,000 to Pima County for the park's purchase.^[1]

• Kennedy Lake at John F. Kennedy Park is located between La Cholla and Mission Road. It is part of Tucson's municipal fishing program. The lake is about 10 acres and 8 feet deep. Small boats and canoes and fishing are allowed but there is no swimming.^[2]

• Lakeside Lake at Chuck Ford Lakeside Park is near the intersection of Silverbell and Sarnoff. It is a small fishing lake where residents can float in small boats and canoes.^[3]

• Silverbell Lake at Christoper Columbus Park is located near the northwest side of the city in Pima County. Like other small county lakes it provides a place to fish and small boats and canoes are allowed in the lake.^[4]

 
Water Quality

On December 16, 2013 the Regional Wastewater Reclamation Department (RWRD) diverted flows from the closed Roger Road WRF to the state-of-the-art Agua Nueva WRF facility allowing Pima County to meet strict environmental standards for effluent discharges into the Santa Cruz River. All City of Tucson reclaimed water needs are supplied by the Agua Nueva WRF.^[6]

The Tres Ríos WRF is the central biosolidsorganic matter recycled from sewage treatment location for Pima County, treating approximately 30 million gallons of wastewater per day while operating 24 hours per day, 365 days per year. The facility was upgraded and expanded as part of the Regional Optimization Master Plan and meets stringent regulatory requirements on effluent nutrient reduction. It has a permitted capacity to treat 50 million gallons per day, which should meet projected population needs until 2030. The facility is permitted for A+ reclaimed water through Arizona Department of Environmental Quality (ADEQ).^[6]

On December 30, 2014, RWRD closed the Randolph Park WRF, which produced high-quality reclaimed water. The wastewater that had been treated at the Randolph Park facility is now being treated at the Agua Nueva and Tres Rios WRFs. The equipment and fixtures will remain so the facility can be used if needed in the future.^[5]

Five smaller WRFs serve small towns and rural areas of Pima County in Arivaca Junction, Avra Valley, Corona de Tucson, Green Valley and Mt. Lemmon.^[6]

Most of Tucson's renewable CAP supply is stored in wells in three locations and then delivered to customers:

• Central Avra Valley Storage and Recovery Project (CAVSARP) which began operating in 2001
• Pima Mine Road Recharge Project (PMRRP) owned by the City of Tucson and the Central Arizona Water Conservation District, which began operating in 2001
• Southern Avra Valley Storage and Recovery Project (SAVSARP), which began operating in 2008^[8]

The system is divided into 37 water service areas, uses 4,500 miles of pipes and 145 booster stations.^[1]

All drinking water, even bottled water, contains some contaminants. Tucson's groundwater contains dissolved minerals and organic compounds, leached from the soil, rock, sediments and plant materials. These include beneficial minerals, including calciumthe chemical element of atomic number 20, a soft gray metal and magnesiumthe chemical element of atomic number 12, a silver-white metal of the alkaline earth series. It is used to make strong lightweight alloys and harmless minerals including chloride,a compound of chlorine with another element or group, especially a salt of the anion Cl bicarbonatea salt of carbonic acid containing the ion HCO₃- and sulfatea salt of sulfuric acid, containing the anion SO₄^2- and metals including iron,a strong, hard magnetic silvery-gray metal used as a material for construction and manufacturing, especially in the form of steel copper,a highly conductive metallic chemical element that is easily formed into sheets and wires arsenica solid chemical element that is used especially in wood preservatives, alloys, and semiconductors and is extremely toxic in both pure and combined forms and lead.a soft, dense, malleable metal with a relatively low melting point These can be beneficial or harmless at low concentrations, but harmful at high concentrations.^[1]

Our groundwater can also contain contaminants resulting from industrial or domestic activities, meaning that Tucson Water must must check approximately 90 regulated and 31 unregulated contaminants. Most regulated contaminants were not detected in Tucson's drinking water.^[1]

Tucson Water follows the guidelines established by the EPA and serves nearly 750,000 people in the Tucson area. Water quality is continuously monitored and in 2019 and 2022 was found to meet all EPA standards.^[1],[8]

Tucson Water also monitors unregulated contaminents to help the EPA decide whether there should be established standards or future regulations concerning these contaminents. Most of these contaminents are not currently health risks.^[1]

Tucson Water voluntarily conducts 396% more tests and voluntarily takes 184% more samples than required by the EPA. The utility's Sentry Program proactively identifies contaminants of emerging concern (CECs) and PFAS which includes biannual sampling at 17 sites on the potable and reclaimed water systems. The utility works with other local water utilities, stakeholders, and partners to set priorities, direct resources, and develop projects, programs, and policies concerning CECs.^[9]

Tucson Water Contaminents 2022[8]
contaminant	units	description	Tucson water	EPA max allowed
disinfection byproducts
haloacetic acids (HAA5)	ppbparts per billion	chemicals formed when disinfectants are used to control microbial contaminants	ND-2.6	60
total trihalomethanes (TTHMs)	ppb	formed when chlorine combines with naturally occurring organic material in water	1.6-41.9	80
inorganics
arsenic	ppb	naturally occurring substance commonly found in groundwater in the southwestern United States	ND-6.7	10
barium	ppmparts per million	occurs naturally at very low concentrations in our groundwater	ND-0.18	2
cyanide	ppb	discharged from metal, plastic and fertilizer factories	ND-5.0	200
fluoride	ppm	an important naturally occurring mineral that helps to form healthy teeth and bones	0.14-0.88	4
nitrate	ppm	a form of nitrogen and an important plant nutrient	ND-5.9	10
selenium	ppb	an important nutrient	ND-2.4	50
sodium	ppm	sixth most abundant Earth element, widely distributed in soils, plants, water	14-69	N/A
synthetic inorganics
atrazine Atrazine Benjah-bmm27 Dec. 24, 2006 Wikipedia Atrazine https://en.wikipedia.org/ wiki/Atrazine#/media/ File:Atrazine-3D-balls.png public domain	ppb	herbicide synthetic organic	ND-0.1	3
endothall Endothall Edgar181 Oct. 27, 2017 Wikipedia Endothall https://en.wikipedia.org/wiki/ Endothall#/media/File:Endothal.svg public domain	ppb	herbicide, synthetic organic	ND-5.7	100
volatile organics
ethylbenzene Ethylbenzene Chem Sim 2001 Dec. 4, 2020 Wikipedia Ethylbenzene https://en.wikipedia.org/wiki/ Ethylbenzene#/media/File: Ethylbenzene-from-xtal- Mercury-3D-bs.png public domain	ppb	discharged from petroleum refineries	ND-0.6	700
toluene Toluene B. Mills Mar. 15, 2009 Wikipedia Toluene https://upload.wikimedia.org/ wikipedia/commons/5/5e/Toluene -from-xtal-3D-balls.png public domain	ppm	discharged from petroleum refineries	ND-0.002	1
xylene Xylene DrBob Jan. 8, 2008 Wikipedia Xylene https://en.wikipedia.org/wiki/ Xylene#/media/File:IUPAC-cyclic.svg CC BY-SA 3.0	ppb	discharged from petroleum refinerise	ND-0.003	10
radioactive elements
alpha emitters	pCi/Lpicocuries per liter, a picocurie is one trillionth of a curie, represents 2.2 disintegrations per minute	measure of radioactivity due to naturally occurring groundwater minerals	ND-7.9	15
radium 226 and 228	pCi/L	naturally occurring radioactive minerals in groundwater	ND-0.9	5
uranium	ppb	highly toxic and radioactive	ND-12	30
other elements
lead	ppb	mostly from home pipes, dangerous to pregnant women and children	0.9	15
copper	ppm	mostly from home pipes	0.108	1.3
disinfectant
chlorine residual disinfection	ppm	added to drinking water at well sites and reservoirs to eliminate microbiological contamination	0.88-1.04	4
microbial agents
fecal indicator	0	common in the environment, rarely harmful, indicates harmful organisms	1 positive sample	0

Tucson Water's Central Arizona Project (CAP) surcharge increased on February 13, 2023 from $0.70 per hundred cubic feet to $1.00 per hundred cubic feet of monthly use. Each July 1, between 2024 and 2027, water rates will increase by 5.5%.^[7]

Nine wells extract contaminated water and deliver it through a pipeline to the Advanced Oxidation Process (AOP) TARP facility, where both TCE and dioxanea synthetic, potentailly explosive and carcinogenic industrial chemical are removed.^[1] TARP facilities treat about 2.18 billion gallons of water per year. The treatment system removed 168 pounds of volatile organic compounds.organic chemicals that evaporate at room temperature^[5]

Some of those living adjacent to, but outside the area served by Tucson Water get their water from wells. All domestic wells in Arizona require Arizona Department of Water Resources (ADWR) permits.^[2]

Pima County regulates onsite wastewater treatment facilities, commonly known as septic systems. Because these systems can contaminate surface water and groundwater contamination, the county requires construction permits.^[3]

The University of Arizona Cooperative Extension offers classes for those who want to build their own wastewater treatment facilities.^[4]

In 2023 the Pima County Department of Environmental Quality (PDEQ) was awarded $1 million as part of the EPA's four-year Climate Pollution Reduction Grant (CPRG). PDEQ is partnering with the City of Tucson and the Tohono O'Odham Nation.^[10]

The grant's goal is to develop strategies for reducing greenhouse gas emissions and other types of harmful air pollution. The plan includes engaging with stakeholders, workforce planning, greenhouse gas reduction, benefits for low-income and disadvantaged communities and opportunities for leveraging other funding sources.^[10]

Sources:

 
Conservation and Sustainability

The City of Tucson and Tucson Water began conservation efforts decades ago. In 1970s local TV commercials, City of Tucson water mascot, Pete the Beak, reminded us to "beat the peak" and not water between 4 p.m. and 8 p.m.^[18]

Tucson's reclaimed water program began in the 1980s, making it one of the first large-scale water-reuse communities in the U.S. The system has about 195 miles of pipe and more than 1,000 reuse customers and 15 boosters. The reclamation system can deliver more than 30 million gallons a day of reclaimed water per day.^[20]

By 1983, Tucson constructed a tertiary treatment plant for the advanced treatment of secondary effluenttreated municipal wastewater received from Pima County and began the pilot aquifer a body of permeable rock which can contain or transmit groundwater recharge program, which was later expanded.^[21]

The Tucson reclaimed water system uses directly filtered water and recovered, recharged groundwater from aquifer storage to meet Arizona Department of Environmental Quality (ADEQ) requirements and to enable parks and golf courses to use reclaimed water.^[21]

In 1984 the city began providing non-potablerefers to water that is not safe to drink renewable, reclaimed water, increasing the available potablerefers to water that is safe to drink water supply.^[21] Reclaimed water is used by 50 parks, 65 schools, including the University of Arizona, 18 golf courses and more than 700 families for outdoor irrigation.^[30]

The system uses 160 miles of pipe and 15 million gallons of surface storage in enclosed reservoirs. During the summer it can provide more than 30 million gallons per day. Using reclaimed water saves the equivalent of municipal water used by 60,000 families.^[30]

Since 1985, Tucson's population grew by more than 226,000 but city water use is the same, even with 75,000 additional Tucson Water service connections,^[19] and since 2000, Tucson has reduced its per-person water use by 27%.^[22]

Implementing water conservation programs has resulted in a 40-year surplus of recharged groundwater. Even if Lake Mead's supply drops below critical levels our city has a Colorado Water Plan to ensure we have sufficient water for our growing population until 2050.^[1]

Tucson's Water Conservation Office was formed in 1990. The city has created a website for residential and commercial conservation programs that includes resources on water reduction, rebates and local water ordinances.^[2]

The city's current water plan was created in 2004.^[28] The Tucson City Council charged Tucson Water to propose a new 2023 plan to ban ornamental grass from new apartments and commercial real estate development as well as removing existing grass.

Tucson Water also helps customers determine how much water we use and how we can reduce that amount by repairing leaks, installing low water-use toilets and irrigation systems, xeriscapinglandscaping requiring little or no irrigation and learning to read our water meters and water bills.^[3],[25]

• conserve water by measuring drainage patterns, contours and water obstructions
• improve soil to create a balance between water storage and drainage
• limit turf areas
• use native plants
• utilize mulch to retain moisture and control temperature changes
• install drip irrigation
• maintain gardens by pruning and removing weeds.^[23]

The city also provides water conservation kits. Users can request a free low-flow showerhead, 5-minute shower timer, toilet tank bag, toilet leak detection dye tablets and bathroom faucet aerator.^[4]

Tucson Code 27-15 Water Waste Ordinance states:

because safe, high quality potable water and reclaimed water are a precious resource, the general welfare requires that the water resources available to the city be put to maximum beneficial use, and that the waste or unreasonable use, or unreasonable method of use, of water be prevented.^[29]

• allowing water to escape from any premises onto public property, such as alleys or streets or upon any other person's property
• allowing water to pond in any street or parking lot to a depth greater than one-quarter inch or to permit water to pond over a cumulative surface area greater than one hundred fifty square feet on any street or parking lot
• washing driveways, sidewalks, parking areas, or other impervious surface areas with an open hose or with a spray nozzle attached to an open hose, or under regular or system pressure, except when required to eliminate conditions that threaten the public health, safety or welfare, but does not apply to residential customers
• operating a misting system in unoccupied non-residential areas
• operating a permanently installed irrigation system with a broken head or emitter or with a head that is spraying more than 10% of the spray on a street, parking lot or sidewalk; this prohibition does not apply unless the head or emitter was designed to deliver more than one gallon of water per hour during normal use
• failing to repair a controllable leak, including a broken sprinkler head, a leaking valve or a leaking faucet
• failure to meet the 50% rainwater harvesting requirement for landscape irrigation set forth in Chapter 6, Article VIII of the Tucson Code applying to non-residential users^[29]

A 2018 study found that nine of a sample of 12 businesses were using Tucson drinking water for more than half their landscaping water. No citations had been issued to violators. A wider study found the vast majority of 41 commercial projects built from 2016 to 2020 exceeded the 50% threshold. Nearly half were drastically out of compliance.^[35]

On October 31, 2022, the first of three new city staffers was hired and charged with with reviewing commericial water plans. Within the next year the Planning and Development Services Department approved 137 plans for new commercial development and inspected them once they were built. All complied with city water use ordinances.^[35]

The City of Tucson Water Department developed the Green Stormwater Infrastructure (GSI) Mini-Grant Program, administered by Tucson Clean and Beautiful. The program enables Tucson neighbors and community groups to install stormwater harvesting features in their neighborhoods. Each Tucson council ward can provide up to $45,000 per year.^[17]

One of Tucson Water's most interesting water conservation efforts is the Zanjero Program. Tucson Water customers can request a free visit by a Zanjero, a water expert with extensive training in indoor and outdoor water conservation and efficiency. The audit includes checking for excessive water consumption, measuring showerhead and faucets flow rates, looking for special water uses such as spas, pools, or misting systems, and analyzing outdoor irrigation efficiency.^[5] Zanjeros can also provide the same water-saving devices accessible from Tucson Water's conservation kits.^[5]

There are many household steps we can take to reduce water use:

The online HomeWaterWorks^[6], Water Footprint,^[7], and DripTap.org^[8] calculators are other resources available to residential consumers to estimate household water use.

The University of Arizona College of Agriculture Cooperative Extension and the Water Management Group provide residents with free classes and information on rainwater harvesting and rainscapes.^[9],[26] Tucson Water has an extensive rainwater harvesting guide.^[27]

Even though most of Tucson's rain occurs during the summer monsoon, during a one inch rain, a homeowner could collect 600 gallons from a 1,000 square foot roof.^[10] Rain harvesting works hand-in-hand with passive water harvesting. Homeowners can build mounds, infiltration basins composed of small rock and sand, small stream beds made of large rock, and gravel trenches to collect rainwater.^[11]

Working with the City of Tucson the Watershed Management Group (WMG) provides gray water and rainwater harvesting classes. WMG also runs the Flow365 Monitor program that enlists the help of local residents can sign up to monitor local creeks and rivers, Hydrate at the Living Lab classes that teach citizens to create sustainable water systems, and provides the Hydro-Local At Home Video Series.^[31]

In 2023 WMG was one of three winners of the Colorado River Basin Water Scarcity Challenge funded by the Gates and Walton Family Foundations. WMG will work with Quantified Ventures to design, finance and scale investible, cost-effective solutions that deliver beneficial outcomes for Colorado River Basin ecosystems and communities.^[32]

Sweetwater Wetlands is a critical part of Tucson's reclaimed water system. It was constructed in 1996 to deal with backwash water from the reclaimed water plant.^[13]

Sweetwater Wetlands now has more than 2.5 miles of pathways. The west entrance is accessible from the bicycle path along the east bank of the Santa Cruz River, where there is a drinking fountain, water bottle filling station and handwashing station.^[13]

Tucson Electric Power (TEP) also conserves water. In 2019, With TEP replaced two units at its Sundt plant with 10 new natural gas-fired reciprocating internal combustion engines (RICE) the are expected to reduce annual water use by 70%.^[14]

TEP's Springerville plant is a Zero Liquid Discharge facility. All of its water is recycled and put into holding ponds now home to birds.^[14]

TEP's headquarters in Tucson were built in 2011 to LEED Gold standards. The building uses low-flow toilets, motion-sensor faucets and captures 191,000 gallons of rainwater annually from the cooling tower and is used for irrigation.^[14]

Arizona Project Wet is a joint program between the City of Tucson and the University of Arizona Cooperative Extension, Water Resources Research Center and Environmental Science. The program provides free water education resources to Tucson's teachers and students.^[15]

A recent water conservation effort is the 40-acre Southeastern Houghton Area Recharge Project (SHARP) located west of Houghton Road on East Drexel Road. It's purpose is to replenish the aquifer by releasing recycled water from the Houghton Reclaimed Reservoir into the SHARP recharge basin, which can recharge 1.3 billion gallons of water per year.^[16]

In November, 2022 30 cities and water districts, including Tucson and the Central Arizona Water Conservation District, signed a water conservation agreement that includes:

• removing ornamental grass
• fixing water leaks
• improving indoor and outdoor watering efficiency
• limiting weekly outdoor watering days
• creating water rate structures encouraging conservation
• minimizing high water-use swamp cooling
• increasing water recycling programs^[22]

During Summer 2022 the University of Arizona completed the installation of 10 foot diamter, 20 foot length underground storage tanks below the east side of the Main Mall between Cherry and Campbell Avenues. Surface water runoff currently flowing south on Cherry Avenue will be diverted into these pipes to prevent flooding of University buildings, including Arizona Stadium and residence halls.^[33]

Sources:

 
Drought

Minor updates to the drought plan were made in 2012 and 2017, with a major revision in October 2020 driven by the 2019 Drought Contingency Plan, an agreement among the seven Colorado Basin states.^[1]

Elements of the most recent drought plan include

• updating drought stages and thresholds for consistency with the 2019 Drought Contingency Plan
• demonstrating a diversified water portfolio
• increasing water savings
• improving infrastructure redundancy
• integrating climate change adaptation planning with One Water 2100
• streamlining drought responses
• incorporating a strategic, data-driven approach to drought planning
• adding response measures to Tier 1 and Tier 2 shortages that could suspend new water service requests.^[1]

 
Challenges

The Tucson Active Management Area (AMA) has been at or around safe-yield since 2010, meaning that the amount of water being removed is less than or equal to the amount being recharged. But outside of metropolitan areas, much of the county depends on groundwater extracted from private wells. Overdraftcondition that results when more water is pumped out of an aquifer than is being naturally recharged has caused subsidence, sinking ground, resulting in infrastructure damage. Some private wells draw shallow groundwater also supporting riparian habitats.^[1]

Groundwater pumping locations often are not located in the same areas where water is recharged, causing a hydrologic disconnect,occurs when water providers store water underground in one location and recover or pump it from another location that has no hydrologic connection to the aquifer where the water was stored which affects groundwater availability.^[1]

• 162nd Fighter Wing AZ Air National Guard (AANG) Project Area
• Air Force Plant 44 (AFP-44)/Raytheon Project Area
• Airport Property Project Area
• Texas Instruments (formerly Burr-Brown) Project Area
• Tucson Airport Remediation Project (TARP)
• West-Cap Project Area
• West Plume B Project Area^[2]

These sites are associated with landfills and industry, polluted by chlorinated solvents, substances used in degreasers, paint strippers and dry cleaning. ADEQ controls the cleanup process.^[1]

CECsunregulated substances often found in pharmaceutical and personal care products that end up in sewers and that cannot be totally removed by usual wastewater treatment processes and PFASa group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals have been found in several Pima County wells and throughout Arizona. These chemicals get into the soil and the water supply.^[1]

In March 2020 Tucson requested help from the Arizona Department of Environmental Quality (ADEQ) to expedite a U.S. Department of Defense statewide PFAS investigation at military facilities.^[3]

During the next 16 months ADEQ developed a plan, conducted a field investigation, installed seven new monitoring wells and designed and constructed the Central Tucson PFAS Project (CTPP) treatment site demonstration project, which began removing PFAS on January 12, 2022. CTPP pumps remove PFAS from contaminated water at a rate of 250 gallons per minute, returning the treated water to a wash where it joins existing groundwater. Tucson Water monitors the site.^[3]

Rivers, streams and lakes that have not attained federal Clean Water Act or met Arizona water quality standards, including some parts of the Santa Cruz River in Pima County, are considered impaired for wildlife, recreation and public water supply use. ADEQ monitors surface water impairment.^[1]

Native fish have survived drought and flash floods but have been declining due to the introduction of non-native species and habitat loss.^[1]

Evapotranspirationprocess by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants will continue to rise and soil moisture will continue to decline.^[1]

Climate change, global warming and increasing temperatures will result in water depletion affecting the environment. As temperatures rise and cities expand, Pima County will see more extreme heat days, strong urban heat island effects, increasing water demand.^[1]

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In 2016 the Arizona Community Foundation announced a $250,000 Water Innovation Challenge prize at the WaterNow Alliance in Tempe. The prize challenged water innovators to find technological or entrepreneurial water sustainability solutions. Twenty-three teams submitted project proposals evaluated by 30 judges.^[1]

The Southwest Water Campus was assembled with an expert panel of water professionals from Pima County Regional Wastewater Reclamation Department, the University of Arizona, Tucson Water, Marana Water, Carollo Engineers, CH2M, AguaTecture, WateReuse, HDR and Clean Water Service.^[2] Their goal was to introduce potable reuse as a viable source for addressing future water needs within Arizona.^[1]

They submitted the Arizona Pure Water Brew Challenge, selected as the winner. The treatment process begins with recycled community wastewater, which passes through ultrafiltration, reverse osmosis,when a solvent passes through a porous membrane in the direction opposite to that for natural osmosis when subjected to a hydrostatic pressure greater than the osmotic pressure UV/advanced oxidation, activated carbon,purified powdered charcoal and chlorine disinfection steps, resulting in pure water. ^[4]

The project engaged and educated the public about purified effluent as a safe drinking water source. The team demonstrated advanced water purification technology by building a mobile water treatment facility, where the public could view the water purification processes as the facility purified recycled water delivered to local breweries as part of a beer tasting competition.^[1], ^[5]

Twenty-six breweries from 12 Arizona cities participated.^[1] Tucson's Dragoon Brewing Company's Clear Water Pilsner was the winning brew.^[3]

In October 2023 the Tucson City Council adopted the One Water 2100 Master Plan. In addition to obtaining new supplies and protecting existing groundwater from contamination, the plan calls for studies, public outreach efforts, demonstration projects and cost-benefit analyses before the city relies on full-scale DPR programs.^[6]

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Resources

Denise Meeks, dmeeks@arizona.edu