Behind the scenes at a major resort on the Las Vegas Strip, an effort is underway at the Bellagio Resort & Casino to reduce water use on a massive scale.

MGM Resorts International is piloting the Strip’s first hybrid cooling system with technology designed to save millions of gallons of water a year.

“The controls, in the first year of use, are learning. And so what the controls need to do is figure out, based on the cooling load of the building and the ambient outdoor temperature, should it be running in wet mode or dry mode,” Michael Gulich, vice president of sustainability for MGM Resorts, said on Thursday.  “We’re still in that first year period of learning,”

The cooling systems are essential to keeping resorts like the Bellagio running. These systems traditionally rely on water to remove heat through evaporation. The new hybrid setup changes that.

Read More: Forget fountains, Bellagio's big water user is cooling towers. Now a hybrid system is in testing