If you are staying in the same place for a long time you can create a heated and insulated water hose so you do not have to drain it ever night. Buy a heat tape that matches the length of your hose as well as some foam pipe insulation at a hardware store, Home Depot, Loses, or Menard's. Lay the heat tape along the bottom of the foam insulation, than put the hose inside the insulation, and use electrical tape every few feet to hold the insulation closed. Attached the thermostat portion of the heat tape to the hose so it senses the water temperature in the hose. Plug the heat tape in and forget about freezing water the rest of the winter. You can find a number of sites on the internet that show how to make this type of a hose set-up ... or find somebody in the park you are in who has an insulated hose and ask them to show you how they made it.