Flagstaff plans $300M new wastewater treatment plant amid infrastructure challenges

The Flagstaff City Council convened for its second day of the Budget Retreat on April 25, 2025, focusing primarily on water services and the pressing need for a new wastewater treatment plant. The meeting began with a brief acknowledgment of ongoing discussions regarding downtown projects, before shifting to the critical topic of wastewater management.

Newly appointed Water Services Director Lee provided an overview of the city's current wastewater infrastructure, which includes two plants: the Wildcat Hill Water Reclamation Plant, built in 1979, and the Rio De Flag Water Reclamation Plant, established in 1996. Both facilities are operating below their capacity due to a combination of aging infrastructure and evolving water treatment standards. Lee emphasized that while the city is not currently at liquid capacity, it is nearing solids capacity, necessitating the construction of a new plant.

The proposed new wastewater treatment facility is projected to cost between $350 million and $428 million, with estimates suggesting a capacity requirement of 14 million gallons per day to accommodate future population growth. The council discussed potential funding strategies, including the possibility of bonds or sales tax options, as the current budget only allocates $25 million for design within the ten-year Capital Improvement Plan (CIP).

Lee outlined two approaches for constructing the new plant: an all-at-once build of a 10 million gallon per day facility or a phased approach that would allow for incremental construction. Each method has its advantages and challenges, particularly concerning operational efficiency and cost management.

The council also explored advanced treatment technologies, such as Membrane Biological Reactors (MBR), which could provide high-quality effluent suitable for indirect potable reuse. The discussion highlighted the need for innovative solutions to meet both current and future wastewater treatment demands.

As the meeting concluded, the council recognized the urgency of addressing funding and design timelines, with a design phase estimated to take around two years. The city is actively seeking creative funding solutions to ensure the successful development of the new wastewater treatment plant, which is essential for maintaining public health and supporting Flagstaff's growth.