I grow most of my own vegetables and fertilize them with the compost from garden waste. I also use organic nitrogen fertilizer that is made locally. I notice almost no change in my water bill. This year I picked nearly 100 ears of corn, fresh lettuce and spinach for 7 months, 12 months worth of green beans, dozens of Jalapenos, dozens of Bell peppers, and 6 100 pound pumpkins (the kids wanted the giant breed for Halloween, normally we grow Cinderellas).
Store bought produce flat sucks compared to my fresh home grown veggies. Plus I find gardening relaxing.