Microsoft has leased a water-treatment plant on its data center site in Quincy, Washington, to the City of Quincy at a purely symbolic annual rate of US$10, helping the city avoid a large capital expenditure in exchange for a discounted water rate.

Christian Belady, general manager of data center advanced development at Microsoft, wrote in a blog post that the project would promote "a long-term sustainable use of a limited natural resource, water, in a desert area that has the added benefit of supporting the foundation of Quincy and Grant County’s growing economy for years to come."

The agreement includes an option for the city to buy the water-treatment plant – which Microsoft has been using to remove minerals from potable water before it would go into its data center cooling systems – after 30 years. The city will operate, maintain and manage the plant during that time.

"By loaning these assets to the city, they were able to save significant construction costs for the new [water] reuse system," Belady wrote.

The city plans to retrofit the plant, expanding it into an industrial-reuse system in two phases. In Phase I, the plant's capacity will be brought up to 400,000 gallons per day and in Phase II, its capacity will reach 2.5m to 3m gallons per day.

In addition to a cheap water rate, Microsoft benefits from the agreement by ridding itself of the need to operate the plant and being able instead to focus on its core business.

The plant serves Microsoft's 500,000 sq ft legacy data center at the site and, to a much smaller extent, its brand new modular data center there. The ITPAC-based modular facility uses very little water because of its extensive use of airside economization (outside air) for cooling.