Oro Valley Water Utility officials have been in discussion with their counterparts at Tucson Water about a possible agreement to trade Central Arizona Project water for treated water.
"From the perspective of Oro Valley Water Utility, these discussions with Tucson Water benefits the water utility and our customers," said Philip Saletta, Oro Valley Water Utility director.
Preliminary discussions focus on Oro Valley trading a portion of its CAP allotment to Tucson, which would use the water at its recharge facility in Avra Valley.
The recharge facility, a series of 11 recharge ponds covering 300 acres, collects water that later trickles through the surface, eventually seeping into the aquifer.
Oro Valley would trade up to 5,000 acre feet of its 10,305-acre-feet allotment of CAP water in exchange for Tucson delivering a proportional volume of treated water to the town.
The trade would lessen the town's reliance on groundwater. Last year, the town pumped more than 8,000 acre-feet of groundwater. An acre-foot equals the amount of water it takes to cover one acre of land in a foot of water, about 325,851 gallons. The total is roughly equivalent to the amount of water a family of four uses in a year.
"This gives us an interim period to preserve and protect our groundwater," Saletta said.
The town would also benefit financially by potentially lowering its payment to the Central Arizona Water Conservation District, which charges for groundwater pumping.
The town pays $305 per acre-foot of groundwater it pumps. It earns credits against pumping by storing a portion of its CAP at Kai Farms in Marana. The farm uses the CAP water in lieu of pumping groundwater. Last year, the farm used about 4,000 acre-feet.
The remainder of Oro Valley's CAP allotment gets stored at other facilities or remains in the system, where CAP sells it to other water providers.
Tucson would benefit by increasing the capacity of its recharge system, Saletta said.
Oro Valley has long-term plans to utilize its CAP allotment, but that requires the construction of significant infrastructure including a pipeline, treatment and storage facilities.
The town has partnered with Metropolitan Domestic Water Improvement District, Flowing Wells Irrigation District and Marana Water to build the CAP delivery system.