Folks, I wanted to give you a link to what we are using here in Atlanta for water storage, rather than small rain barrels. I have a linked system of these that adds up to over 600 gallons of rain water.
These originally were used for soap, but the ones I use were used for food grade vinegar that is used to clean poultry houses, so anywhere you have a poultry industry, you should be able to find these.
https://atlanta.craigslist.org/nat/grd/4198733043.html