Published on 09/20/02

Rain harvesting system: New twist, old idea

By Sharon Omahen
University of Georgia

People have collected rainwater in barrels and buckets for generations. Today, a more sophisticated rain harvesting system can provide homeowners and their landscapes insurance against water bans.

"Collecting water or harvesting rain has been done throughout history when water is scarce," Paul Morgan said. "What's different now is the way we do it."

Morgan, operator of RainHarvest Company of Snellville, Ga., specializes in systems that allow homeowners to collect "almost every drop of rainwater" that hits their roofs.

Metal roofs are best when it comes to rain collection. "You lose a lot of water when it runs across an asphalt shingled roof," Morgan said.

Stored Underground

Here's how the system works. Rain falling on the roof is channeled through the gutters by pipes that lead to an underground collection tank or cistern. The water is stored there until the homeowner chooses to use it for landscaping needs. At that time, an electric pump brings the water to the surface.

"Our goal is to collect every bit of rainwater that falls on a site," Morgan said. "That's impossible, but it's still our goal."

During an average rainfall, rain-harvesting systems collect about two-thirds of a gallon of water for every square foot of roof, he said.

"If it rains once a week, you'll collect enough water to irrigate most home landscapes," he said.

Seeing rain water "lost" prompted Morgan to expand has landscape business to include rain harvesting.

"I saw a lot of water running down the street, and I saw it as a resource that should be saved and used," he said. "I also saw the Chattahoochee (River) turn orange every time we had a heavy rain, and I thought about how we could prevent this and reduce a lot of erosion if we captured rain water."

Over the past two years, Morgan has installed three home rain harvesting systems. He is installing his first commercial system atop the horticulture building at the Griffin campus of the University of Georgia College of Agricultural and Environmental Sciences.

Demonstration Site

"Our site will serve as a demonstration project," said Wayne Gardner, head of the UGA Center for Urban Agriculture. "We plan to install landscaping around the building in nine different zones, with each zone having different water needs. And the rainwater will be, chemically, a much better product for the plant materials."

UGA researchers view this system as yet another way to combat Georgia's drought conditions and conserve water.

"Above all, we are searching for long-term solutions to using this precious commodity," Gardner said. "One day our state's drought is going to break, and when it does, we are still going to have water issues to face in Georgia."

The crew installing the rain harvesting system uncovered drastic proof of our state's drought conditions.

The Drought Runs Deep

"We dug down 9 feet to put in the water collection tank and found no moisture at all," Gardner said. "We've gotta have rain. And it's going to take a lot of moisture to get us back to where we need to be."

Besides rain from the gutters, the rain harvesting system in Griffin also collects condensation from the building's air-conditioning units. In just one day, the system collected 30 gallons of water from the UGA building's three air-conditioning units.

"We can also link to ice maker drains and refrigerator and freezer drains," Morgan said.

The unit is equipped with a gauge that shows how much water has been collected.

"We have a 1,700 gallon-collection tank, and when it fills up, an overflow value opens," Gardner said. A filtration system keeps debris from collecting in the underground tank.

Morgan feels more people will become interested in the concept as the drought worsens.

Water Ban Insurance

"When total outdoor water bans hit, I think people will be more receptive to this idea," he said. "I think of it as insurance. If you own a business and you just put in $70,000 worth of plants and the city says you can't water, what do you do?"

Morgan says a typical home rain harvesting system costs about $3,000.

"Right now, water costs $3 for a thousand gallons, so people aren't apt to run out and put in a rain harvesting system," he said.

Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.