Most home sprinkler systems use an average of 16 gallons of water per minute to water the lawn.
Larger sprinkler systems or commercial sprinkler systems may use an average of 50 to 100 gallons of water per minute and sometimes more depending on the size of lawn they are watering and how large of a sprinkler system they have.
The amount of water per minute also depends on the sprinkler head size and water pressure to those sprinkler heads.
But for home sprinkler systems that pop up out of the ground they use at most 16 gallons of water per minute of run time.
The longer you run them the more water you will use and in an hour of run time at 16 gallons per minute you would use 960 gallons of water.