Yes, it does get below freezing in Arizona in the winter (Sierra Vista). Last winter when the temperatures were in the 20s for a couple of 10 day periods I learned different ways of keeping the pipes from freezing. I wrapped the hose and faucet head in heat tape, insulated the hose, and put a thermostatically controlled outlet on the heat tape. I ran a small dribble of water from the kitchen cold water faucet at night. One night many of the water outlets in the park froze (including mine), but not my hose. To fix that issue I put a plastic storage box over the outlet to keep the heat in. I set my furnace thermostat on 55 degrees to get some heat in the belly at night. I put a remote thermometer in the basement to get an idea how cold it was getting at night. I kept my holding tanks closed to use any residual heat in the fluids to keep them from freezing and to keep fluids from freezing in the sewer hose.
Two additional ideas that worked for me was to keep the 12 volt lamp in the convience compartment on. Then I also installed a 75 watt light fixture with a plug for the basement outlet in the area behind the convience center where all the plumbing and the water pump reside. You would be surprised the amount of heat those two lights produced in a critical area of your plumbing.