In 2004, SAWS began injecting water into its aquifer storage and recovery system, a water bank that allows the agency to take water from the Edwards Aquifer, its main source, and store it for future use. The utility, which serves more than 1.6 million people in the San Antonio area, credits the aquifer storage system with its ability to avoid every-other-week-watering restrictions throughout one of the most severe droughts in Texas history. The Edwards Aquifer Authority ordered cuts in pumping, as much as 40 percent in August 2014, for all permit holders during the drought to protect endangered species. […] the day will come when drought returns again, and the aquifer storage system is a more effective way to bank water than a surface reservoir because none is lost to evaporation, Labatt said.

Source: SAWS underground water bank more full than ever – San Antonio Express-News