Scottsdale City Council reviews water supply options, sets path forward

Scottsdale City Council supported moving forward with projects to conserve more water, expand reuse and move existing supplies more efficiently as the city prepares for potential Colorado River reductions.

During an Oct. 20 study session, Scottsdale Water staff and consultants presented options ranging from near-term improvements to the city’s distribution system to larger investments in advanced water purification. The discussion examined how much water each option could provide, how quickly it could be available and what it would cost.

The city’s approach combines conservation, additional water supplies, regional partnerships and infrastructure improvements to reduce reliance on the Colorado River.

Preparing for potential reductions

Staff outlined a potential 17% reduction in Scottsdale’s Central Arizona Project allocation for 2027 if a proposed Lower Basin agreement is finalized. CAP delivers Colorado River water to the city.

That reduction would leave Scottsdale with more CAP water than it delivered in 2025, allowing the city to maintain current operations under the scenario presented. Staff emphasized the importance of continuing to develop alternatives as Colorado River conditions evolve.

Scottsdale delivered about 82,600 acre-feet of drinking water in 2025. Total deliveries, including reclaimed water, were about 90,800 acre-feet. An acre-foot is approximately 326,000 gallons.

The city draws on several sources, including Colorado River water, Salt and Verde River supplies, groundwater and reclaimed water. Staff reported that overall deliveries remained relatively consistent from 2021 through 2025, with a slight decrease despite population growth.

Making better use of existing water

Among the near-term options is improving the system’s ability to move Salt River Project water treated at the Chaparral Water Treatment Plant into central and northern Scottsdale during high-demand summer months.

Consultants identified distribution improvements that could help the city use water already available to it while providing flexibility for future supplies.

Scottsdale is also pursuing recovery of water from city-owned land in the Harquahala Valley as a shorter-term supply option.

Another option is a sixth wastewater pump-back station near Indian Bend and Hayden roads. The station could return an additional 4 million gallons of wastewater per day to the Scottsdale Water Campus for treatment and reuse.

That additional water could support several strategies, including groundwater recharge and advanced water purification.

Consultants also evaluated a pipeline that would deliver highly treated recycled water from the Water Campus to the CAP canal. That option would require coordination with the Bureau of Reclamation and CAP.

Weighing advanced water purification

Advanced water purification would build on Scottsdale’s existing treatment system to produce drinking water from recycled water under state requirements.

Consultants presented several configurations, with potential production increasing when purification is paired with additional wastewater collection. The options evaluated would maintain reclaimed-water deliveries to golf courses served by the city’s reclaimed-water distribution system.

Costs were a central part of the discussion. Two purification options without the sixth pump-back station carried estimated capital costs of approximately $133 million and $164 million, with estimated annual operating costs of $6.3 million and $7.3 million, respectively.

City Manager Greg Caton said the analysis was intended to give council a clearer understanding of costs and alternatives before moving forward.

Conservation and regional partnerships remain priorities

Staff also reviewed conservation services, including outdoor water efficiency checks, irrigation rebates, grass removal incentives and leak detection assistance.

About 75% of customers now have advanced meters that support hourly water-use information through the city’s WaterSmart portal. The portal helps customers track use and identify potential leaks.

Scottsdale is also evaluating additional conservation measures, including rainwater harvesting and hot-water recirculation incentives, through an update to its drought management plan.

Public engagement is planned for this winter, with the updated plan expected to return to council for approval in spring 2027. The city remains in Stage 1 of its current drought plan.

For longer-term supplies, Scottsdale is participating in the ongoing Bartlett Dam expansion study. Construction is currently scheduled to begin in 2035, with completion anticipated in 2045, placing the project furthest out on the city’s water supply timeline.

Moving projects forward

Council supported the projects outlined by staff, which will be included in upcoming funding appropriations for council consideration. Staff will advance project planning, work through regulatory requirements and gather public input on conservation strategies.