That is just SO wrong, Alice, since your irrigation water certainly doesn't have to go out through the sewer system.
We're not even on the sewer system here, so no issues like that. Our usual monthly bill is around $20 for the two of us even with a swimming pool.
Good on you, Jim for eliminating half of your grass, too. Watering grass uses up an astounding amount of water in this country. Other places are way ahead of us in eliminating turf grass that needs to be watered. I don't mind grass that serves a purpose like sports fields and such, but lawns just "for show" make me nuts. Not only the water but the chemical warfare that it takes to grow a nice lawn, especially in Florida just has me wondering how long before the "lawn mindset" will be gone from our culture for the good of the overall environment.