You can even take it an extra step by keeping one by your sink mark it undrinkable and before you throw any water away throw it in the jug. Freeze the jug and you have free ice. Use an empty milk carton for storage of anything. Socks, pens, children's toys. Cut the top off the milk jug and use for carrying around garden tools.
Milk jugs make great organizers.
Cut off the top and use for whatever comes to mind. Fill an empty squirt bottle with water and keep it near your iron for refilling. Cut off the top, poke holes in the bottom and they are great for starting seeds. Use empty bottles for plant food. Mark them and store them outside.