Benefits
Residential irrigation can account for 40% of domestic water consumption in a given municipality. Rain barrels not only store water, they help decrease demand during the sweltering summer months. Only 1/4 inch of rainfall runoff from the average roof will completely fill the typical barrel.

Collection of water from rooftop runoff can provide an ample supply of this free "soft water" containing no chlorine, lime or calcium and fewer sediments and dissolved salts than municipal water. Chlorine-free rain water helps maintain a healthy biotic community and is ideal for many applications including biodynamic and organic vegetable gardens and indoor tropical plants like ferns and orchids. Water from a rain barrel can also be used for automobile washing and cleaning household windows.

Using a rain barrel reduces a property owner's demand for treated tap water, thereby saving money on monthly water bills. Rain water diversion also helps decrease the burden on water treatment facilities and municipal drainage systems during storms. The storage of rain water is also recommended for general emergency preparedness, or for areas prone to disasters or drought.

A rain barrel installed at a school or municipal building can serve as a helpful educational tool to teach the public about water conservation and runoff. ²

Typical rain barrel set-up for a residential property.
For residential applications, a typical rain barrel design will include a hole at the top to allow for flow from a downspout, a sealed lid, an overflow pipe and a spigot at or near the bottom of the barrel. The spigot can be left partially open to detain water or closed to fill the barrel. A screen is often included to control mosquitoes and other insects. Larger systems for commercial or industrial use can include pumps and filtration devices. ³

A good formula to remember: 1 inch of rain on a 1,000 sq ft roof yields 623 gallons of water. Calculate the yield of your roof by multiplying the square footage of your roof by 623 and divide by 1000. ⁴