Also known as rainwater tanks in many parts of the United States, rain barrels are water containers wherein rain water from rooftops is collected and stored. This rain water often comes from rain gutters that are found on many rooftops. Related storage tanks called rainwater tanks on the other hand are used primarily for the collection of harvested rain. Rain barrels are sometimes installed to collect water running off from concrete patios and even driveways.

Rain barrels actually have many uses, not the least of which is the storage of rain water for later use. With this usage, they can greatly decrease the consumption of water from the utility supply, which is of course a great benefit in terms of economical and environment considerations. Of course being able to store rain water also results in a certain measure of self sufficiency, since doing so will allow you to be less dependent on mains water to some degree, depending on how much water you consume on a regular basis.

The stored water from the rain barrels may itself be used for garden irrigation and other agricultural purposes, for household uses such as flushing toilets, washing clothes and cars, and in some cases even for drinking. This can be a great benefit in areas where water is less available, cost prohibitive or unsafe to drink. This is one of the main reasons why rain barrels can often be seen in areas with arid climates, wherein water is collected during the rainy season and used later when water is scarce. In any case, water that is collected from rain barrels must still be protected against contamination and filtered if possible.