I live in a 1983 ranch with my husband and mother-in-law. Our electric bill for August was $236 (A/C was set at 80) and Sept was $179 (less use of A/C). My water/sewer bill runs right at $100 a month. We do not have a pool and we have minimal landscaping. The plants I do have are native to the desert which helps. Many here in Havasu have much higher bills. My guess is because they don't conserve. I don't wash my own car, or wash the dirt off the driveway. We use a programmable thermostat, only run the dishwasher and washing machine for full loads, and we have energy efficient windows. Little things do make a difference.
The highest electric bills run from mid June to mid Sept. That's when it is muggy and hot. Otherwise the weather makes it possible to open the house up or keep it closed to keep the temperature consistent and comfortable. Heat is used only for a small time in Jan & Feb.
We moved here from NH and love it!