the majority of usage goes towards power generation (https://water.usgs.gov/edu/wateruse-total.html). urban areas consume the power, but they dont produce it. they hide their water usage in the rural areas.
Looking at that data it appears that a majority of California's water for power generation is coming from salinated sources, so at least for California the largest user of fresh water sources is still irrigation (agriculture).
Either way, the point that agriculture takes a lot more water than people watering their lawns still stands.
If you look at aggregate water usage for California agriculture uses 4X "urban" and "urban" includes industrial, golf courses, parks, etc.
So even if lawns are using more area they are much less water intensive than agriculture.
http://www.ppic.org/publication/water-use-in-california/