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How Does a Rain Barrel Work?

By Jennifer Loucks ; Updated September 21, 2017


Using rain barrels for water collection dates to ancient times when the process was used in the Middle East, where water was a rare resource. Rain barrels are used as a collection device for rain water that falls on a home's roof and through a downspout. While barrels are available for purchase from gardening retail stores, homemade barrels are a low-cost investment and easy to make. When built or set up properly, rain barrels require little maintenance.

Rain barrels are appealing for dry environments where rain is scarce and water use is expensive. The use of rain barrels is making a comeback as green and environmentally aware practices become more popular. Collection of water with a rain barrel also reduces runoff, which pollutes and burdens the sewer system.

How it Works

Rain barrels made out of 55-gallon food-grade barrels offer ultraviolet-radiation protection, are easy to clean, and prove sturdy for water collection. The barrel is placed next to the downspout which is reworked and attached to a hole in the barrel's top cover. Near the bottom of the barrel is a spigot with a hose attachment to easily use the water. Most rain barrels have overflow spouts that, in the case of heavy rain, diverts excess water out of the barrel without damaging the barrel, the home or surrounding area.

The top of the barrel is covered to prevent contamination by debris or animals. The covered top also prevents mosquitoes from using it as a breeding area. Having the barrel slightly elevated provides easier access to the spigot. Place stone or pea gravel under the barrel to assist with drainage during overflow condition with the barrel on a cement block for proper elevation.

Uses for Collected Water

Harvested water is used to water gardens and plants. The water from a rain barrel provides a free source of water for outdoor watering. Rain water is better for plants than chemically treated city water. The barrels are convenient as they can be placed in areas where water is not available or difficult to reach. A standard or soaker hose attached to the spigot allows for ease in watering plants and flowers.

The collected water should never be used as a source of drinking water or for cooking and bathing. Disconnect the rain barrel if chemicals are used on the roof or house until residue has been washed away. Rain barrels should be disconnected during winter months to prevent ice buildup or damage to the barrel or downspout.


About the Author


Jennifer Loucks has been writing since 1998. She previously worked as a technical writer for a software development company, creating software documentation, help documents and training curriculum. She now writes hobby-based articles on cooking, gardening, sewing and running. Loucks also trains for full marathons, half-marathons and shorter distance running. She holds a Bachelor of Science in animal science and business from University of Wisconsin-River Falls.