A decorated rain barrel is connected to a downspout in a backyard, where it will capture rainwater for watering garden beds.

Robin Blair does what she can to help her plants thrive. She plants them in good soil and keeps the weeds away. She also waters them regularly with rainwater captured in barrels in the yard of her Shrewsbury, N.J., home.

Collecting the water is easy, she says, and good for her plants and the environment.

“Rainwater is void of chemicals. It’s kinder to plants and landscaping,” says Blair, who has two rain barrels and a cistern tied into her gutter system. “Water is a precious resource. Why not collect rainwater and reuse it?”

Rain-barrel use and classes are on the rise around the country, according to gardening and conservation experts. Although the concept of capturing and reusing rainwater has existed for thousands of years, many gardeners and environmentalists are revisiting it because of concerns about storm-water runoff and water conservation.

“It’s one of our more popular classes,” says Madeline Samec, a horticultural program assistant with the St. Johns County Extension Agency in St. Augustine, Fla. “We almost don’t have to advertise.”

Most rain barrels hold around 55 gallons of water and are connected to a downspout. They normally have an overflow pipe that detours excess water away from a home’s foundation, and a filter that prevents mosquitoes from entering. Rain barrels also have a tap that can be used to fill watering cans or connect to a hose.

A 55-gallon barrel connected to a 1,000-square-foot roof will fill up during a 1-inch rain. The barrels can be purchased for $50 to $120 each, or constructed out of food-grade drums.

In addition to watering the garden, some people use rainwater for koi ponds or aquariums, says Dotty Woodson, extension program specialist for water resources at Texas AgriLife Extension Service in Dallas.

She said many rain-barrel users like that rainwater does not contain chlorine, fluoride or other chemicals that municipalities use to treat water.

While investing in a rain barrel does help the environment, it’s not likely to shave a lot off of a homeowner’s water bill, Woodson says.

A rain barrel can be connected to a gutter system without too much difficulty, the experts said.

First, homeowners need to remove a section of downspout and replace it with flexible tubing. When the rain barrel is in use, the tubing should run from the downspout to the barrel. When the rain barrel is not in use, the tubing should reconnect back to the downspout.