If You Are Preparing Your Own Containers of Water...
https://www.fema.gov/pdf/library/f%26web.pdf
(Page 8-9)
If you decide to re-use storage containers, choose two-liter plastic soft drink bottles – not plastic jugs or cardboard containers that have had milk or fruit juice in them. The reason is that milk protein and fruit sugars cannot be adequately removed from these containers and provide an environment for bacterial growth when water is stored in them.
Cardboard containers leak easily and are not designed for long-term storage of liquids. Also, do not use glass containers, because they are heavy and may break.
Preparing Containers
Thoroughly clean the bottles with dishwashing soap and water, and rinse completely so there is no residual soap.
Additionally, for plastic soft drink bottles, sanitize the bottles by adding a solution of 1 teaspoon of non-scented liquid household chlorine bleach to a quart (1/4 gallon) of water. Swish the sanitizing solution in the bottle so that it touches all surfaces. After sanitizing the bottle, thoroughly rinse out the sanitizing solution with clean water.
