The amount of gallons of water that a sprinkler system uses is around 1,020 gallons per hour per each sprinkler head if you have the in ground sprinkler system.
So if you run 4 sprinkler heads on a sprinkler system then you would use around 4,000 gallons of water per hour.
That seems like a lot but it's not too bad to keep your lawn watered and healthy.
Having a nice green lawn helps keep your house looking good and helps your yard look good.
The green lawn makes your house and yard look good which adds curb appeal and also helps your house increase in value.
But if you use 1 sprinkler on a garden hose you would use around 1,020 gallons of water each hour of run time.