SAN ANTONIO — Drilling rigs in the midst of cow pastures are hardly a novelty for Texans. But on a warm May day at a site about 30 miles south of San Antonio, a rig was not trying to reach oil or fresh water, but rather something unconventional: a salty aquifer. After a plant is built and begins operating in 2016, the site will become one of the state’s largest water desalination facilities.

“This is another step in what we’re trying to do to diversify our water supply,” said Anne Hayden, a spokeswoman for the San Antonio Water System.

More projects like San Antonio’s could lace the Texas countryside as planners look to convert water from massive saline aquifers beneath the state’s surface, as well as seawater from the Gulf of Mexico, into potable water. The continuing drought has made desalination a buzzword in water discussions around the state, amid the scramble for new water supplies to accommodate the rapid population and industry growth anticipated in Texas. But the technology remains energy-intensive and is already causing an increase in water rates in some communities.

“If you look around Texas and you look at the climate situation and the fact that the reservoirs are being drawn down, there just isn’t much of an alternative,” said Tom Pankratz, the Houston-based editor of the Water Desalination Report, who also does consulting for the industry.