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A barrel harvesting rainwater

AUBURN UNIVERSITY, Ala. – Harvesting rainwater seems like something that you might see in an “off-the-grid” TV show. However, collecting roof runoff actually could have some benefits for both your community and the environment.

Collecting Rainwater

Conventional stormwater practices can carry pollutants great distances, cause flooding and prevent groundwater tables from replenishing. Collecting rainwater reduces runoff from roofs, driveways and other impervious structures. Environmental Protection Agency engineers estimate that domestic communities can save millions of gallons (and dollars) of water by practicing rainwater harvesting.

Agricultural operations could save even more than their urban counterparts. Adding rainwater harvesting systems to already-robust water conservation methods–like terrace rows–will help farmers minimize their irrigation costs.

Harvesting rainwater is also useful in drought preparation, water management in flood and erosion-heavy areas and reducing demand on local water systems. Some plants also prefer rainwater because it contains almost no chlorine or other additives often found in supplied water.


With the recent rise in inflation, the initial price tag of a rainwater harvesting system may be a bit uncomfortable. Barrels, gutters, pipes and other parts are expensive.

However, according to experts from the Alabama Cooperative Extension System, a single inch of rain on a 1,000 square foot roof can produce 600 gallons (or about one and a half hot tubs) of harvested water. The formula for calculating a roof’s rainwater harvest is as follows:

catchment area(sq. feet) x rainfall(inches) x 0.5 = harvest water (gallons) 

Installing a rainwater harvesting system can be as simple or as complex as a homeowner wants it to be. People can easily clean smaller barrels, but systems are available to catch debris before it flows into larger cisterns.

According to Laura Bell, an Alabama Extension water program coordinator  the most important part of installation is placement.

“Where you place your rain barrel is determined by where you’re collecting rainwater, how you want to use the water you collect and where the location is safest and most sturdy,” she said.

It may be helpful to print out an aerial view of the building where installation will take place. Determine which cistern is needed and which eave or corner to pull water from. If a garden or flowerbed is nearby–or if the water will be used to wash cars and pets–consider placing the barrel nearby.

Personal Choice

It’s ultimately up to the homeowner to decide if a harvesting system is right for their home. Because there are many ways to mitigate water issues, Bell says, a rainwater harvesting system may not be for everyone. Whether a homeowner should try harvesting rainwater or simply building a rain garden, they will have to make that decision using tools and resources available to them.

If deciding on rainwater harvesting or other water conservation methods, homeowners can check out the Alabama Extension publication A Homeowners Guide to Rainwater Harvesting in Alabama.

More Information

The Alabama Watershed Stewards is an educational program that works to promote healthy watersheds and increase the understanding of water pollution. The program also provides residents the knowledge and tools they need to prevent and resolve local water quality problems. For more information on this program, visit the Alabama Extension website at www.aces.edu.

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