Some manufacturers have an abundance of unwanted barrels that they would love to give away. Sometimes you may be able to find barrels on Craigslist. However, if you are purchasing or acquiring a “recycled” 55-gallon plastic barrel to modify into a rainwater harvesting collection unit, be sure the barrel is food grade. This means that the only material in the barrel was food and not chemical. It is preferred to find a barrel that has a removable lid, but this may be challenging. Even a barrel with a “bung” at the top can be converted in to a rainwater harvesting unit. Additionally, be sure the barrel is a dark color, such as blue, black or green. You can use an opaque-colored barrel, such as white, but it will require a little more attention to prevent algae from growing.