This won't work. NOt only will the NSA NEVER allow this to happen as there are already deals out the wazoo about making sure they have water (example being that the NSA gets their water cheaper than the normal rate), the organization behind OffNow, the 10th Amendment Center is corrupt and dishonorable beyond belief. For instance they have claimed work as their own when it was just a rivals organization called PANDA, also if you look at who actually is funding them it reaches to a common group of the Rockefellers, the Fords, and a man by the name of George Soros. Basically the 10th Amendment center is funded to "try and shut off the NSA's water" by the people who ensure that the spying continues.
I've never truly understood water cooling in computer setups, but my thought had always been that it doesn't utilise continually running water (ie like when having a shower), but by having water tanks filled, then pumping the water in/out/across the heatsinks; ergo, if the Utah data centre had a tank holding a few gigalitres, then they aren't reliant upon whether the mains is turned on of off, as they have the water already on site. (Someone please correct me if I'm wrong) Even if they shut the water off, it's not a stretch of the imagination that water tanks would be built, and water carrying helicopters are chartered to fly in the required h2o.