An activist group is mounting an effort to force the state of Utah to shut off the water supply to the National Security Agency's huge data center in Bluffdale, Utah. The OffNow coalition wants to pass state legislation that "would ban Utah from participating with or assisting the NSA in any way in the implementation of their warrantless spying program."

The effort appears to be a political longshot, but gained widespread visibility this week when it was featured on USNews, Time and The Drudge Report.

The OffNow coalition is targeting what it calls the "Achilles heel" of the NSA data center - the fact that it will require a large volumes of water (more than 1 million gallons a day by some estimates) for the cooling systems for its servers. The NSA purchases its water from the city of Bluffdale, which has a wholesale supply agreement from the Jordan Valley River Conservancy District. OffNow notes that the Jordan Valley district is a subdivision of the state of Utah, and thus presents an opportunity to use state-level legislation to pursue a denial of water service to the NSA.

The group is invoking a legal principle known is “anti-commandeering,” which holds that the federal government doesn’t have the authority to force the states (or local communities) to carry out federal laws or regulatory programs. OffNow says a Utah legislator has agreed to introduce its bill, but is not yet willing to come forward until the legislation is finalized.

To date, most of the political influence in the region has been wielded to support the NSA data center project, including an agreement udner which Bluffdale will sell the NSA water at below-market prices to boost economic development in the town. The NSA business provides enough revenue for Bluffdale to build extensive water infrastructure, which will allow it to open up new land for commercial development.

Without the NSA revenue, it would have been 15 years before Bluffdale could have afforded to bring water to that area, Bluffdale City Manager Mark Reid told the Salt Lake Tribune. "It got us a ton of infrastructure, water infrastructure, in places we wouldn't have it," Reid said.

The enormous volume of water required to cool high-density server farms is making water management a growing priority for data center operators. The move to cloud computing is concentrating enormous computing power in mega-data centers containing hundreds of thousands of servers. In many designs, all the heat from those servers is managed through cooling towers, where hot waste water from the data center is cooled, with the heat being removed through evaporation. Most of the water that remains is returned to the data center cooling system, while some is drained out of the system to remove any sediment, a process known as blowdown.

As the scale of these huge facilities has increased, data center operators have begun working with local municipalities, water utilities and sewage authorities to reduce their impact on local potable water supplies and sewer capacity.