Good containers for storing water are food-grade water containers. This type of water container is available at camping and outdoor supply stores. For drinking water, commercially-packaged bottled water that hasn't been opened is usually best.
Avoid using containers that can't be sealed tightly, can break or have been used previously to store cleaning products or other chemicals. It is also not a good idea to use milk jugs, fruit juice bottles or cardboard containers of any kind. Wash and sanitize the container before storing water in it, making sure it is rinsed fully. Store water at room temperature and write the storage date on the container.