The average automatic sprinkler system in San Antonio uses 2,000 gallons when it runs through one entire cycle. Be sure your system is tuned properly and there are no leaking or broken sprinkler heads. Water no more than 1 time per week during water restrictions and once every three weeks during the fall and winter when the grass is dormant. In the absence of restrictions in warm weather, water twice per week or less depending on your grass type, amount of shade available and soil depth.