Jennifer Schultz Nelson
Extension Educator, Horticulture
Using a rain barrel is a simple way to respect our environment as we mark the 41st anniversary of Earth Day this April. Rain barrels are a very fashionable "green" landscape choice nowadays. But they are nothing new. People have been collecting rainwater for hundreds of years, but as the saying goes, "everything old is new again".
Most of the commercially available rain barrels range from 55 to 75 gallons in capacity, which will actually fill quickly with just a small amount of rain. We talk about getting however many inches of rain, but we seldom if ever think about the volume of rain actually coming down in a given area. On a thousand square feet of roof area, one inch of rain is about 623 gallons of water—way more than enough to fill a typical rain barrel. On a much larger scale, one inch of rain on the University of Illinois Assembly Hall is reportedly in excess of one million gallons!
There are several reasons why people go to the trouble of capturing the rainwater than falls on their property:
• Capturing rainwater helps conserve fresh water, one of our most precious resources.
– Rain barrels allow homeowners to utilize water that would otherwise ultimately be lost as storm drainage.
– Use of rain barrels reduces volume of water burdening community storm drains, ultimately lessening impact of runoff on local bodies of water.
• Generally speaking, rainwater is good for plants. It lacks the harsh minerals of well water, and does not contain chlorine like municipal water sources.
• Using free rainwater helps homeowners save money on household water costs.
– During the summer months, 40-50% of a household's water use is for gardens & lawns. According to the Environmental Protection Agency, a typical household will save about 1,300 gallons of water during the summer by using a rain barrel for irrigating their landscape.
There are a few safety issues to keep in mind when using rain barrels in the landscape. They can pose a drowning risk if the openings are large enough for young children, wildlife, and pets to fit through.
A full rain barrel is also heavy. Water weighs just over 8 pounds per gallon, so a 55 gallon rain barrel weighs nearly 460 pounds. Make sure your rain barrel is secure, with no risk of it tipping over on passersby.
It's also worth noting that rainwater from a typical rain barrel is usually not considered safe to drink, for either pets or people. This is because the rainwater carries with it whatever bacteria or chemicals that may be present on your roof surface.
While it's pretty clear that drinking rainwater from a rain barrel is a bad idea in most cases, there is a lot of debate on the safety of using this water to irrigate edible crops.
Unfortunately, there is not much in the way of research-based evidence to support the safety of using rain barrel water on edible crops, but also not much out there to say it is a clear risk either.
There are some reports of rain barrel water having measurable quantities of potentially harmful bacteria and/or chemicals leached from roofing materials. This is highly variable due to differences in roofing materials, and whether or not the roof has things like animal droppings on it that would be a source of harmful bacteria.
However, there is also debate on whether plants would be able to take any of it up, and if so, accumulate it in high enough levels to cause harm to those consuming these crops. Some sources argue that the risk is more from eating parts of the plant that actually contact the water, like lettuce or other greens, as opposed to fruits like tomatoes or peppers.
There is so much debate on this subject, and so many questions unanswered, the most responsible recommendation I can make is for homeowners to be extremely conservative, and avoid using rain barrel water on edible crops. Until the research tells me otherwise, this is the safest route to take.
In my mind, the benefits of using a rain barrel far outweigh the risks. It's tempting to disregard the impact of using a rain barrel, since each individual barrel captures only a small fraction of the rain falling on a particular property. But as more people use at least one rain barrel, the impact increases dramatically. Our efforts to be "green" don't necessarily have to be huge. Every little bit counts.
University of Illinois Extension Master Gardeners in Macon County have been hosting Rain Barrel Workshops since 2008. While they don't have any more workshops scheduled this spring, they do have some ready-made rain barrels available for sale at the Extension office for $50. Call (217) 877-6042 if you are interested in adding one of their rain barrels to your landscape.