Rainwater Harvesting 21678

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Rainwater Harvesting

Part 1. A growing industry with some challenges ahead

Wednesday, May 22, 2013

By Steve Goldberg

Although various forms of rainwater harvesting have been used for thousands of years, as an organized industry, it is still in its infancy. At present, no national standards are in place regulating its use, although various states and municipalities have begun promulgating laws concerning how rainwater may (or may not) be used.

The rainwater harvesting industry has a national organization, the American Rainwater Catchment Systems Association. It is presently headed by David Crawford, president of Rainwater Management Solutions in Salem, VA.

A Word From the President
“The field is really ramping up,” says Crawford. “Actually, it has been over the last four or five years. You see EPA pushing it, localities pushing it. It’s an opportunity to collect water from off of roofs, and in fact reuse that water, keep it onsite, which eliminates a huge portion of your stormwater runoff.”

There are a variety of methods of collecting rainwater—rain barrels, aboveground or underground cisterns, and other collection devices. Such harvested rainwater is frequently used for irrigation, but can also be a source of water for flushing toilets, washing vehicles, and, in some cases, for drinking water.

Whether these systems can offer a financial payback for homeowners has been a point of contention, but Crawford insists that it is possible.

“When you look at the value of water, with people now getting $300, $400, and $500 water bills, the return on investment is much better on residential than it had been in the past, based on the cost of water going up, the water that you’re saving, and the new rooftop tax or impervious surfaces tax that a lot of municipalities are charging now,” he says.

Crawford notes that a number of communities are now offering rebates or reduced stormwater fees for homeowners who install a rainwater harvesting system or who disconnect their gutters from the stormwater system.

It seems that the nonresidential side is already seeing sufficient reason to install various rainwater harvesting systems.

“If you look at the volume, the numbers, the commercial is way above the residential, simply because the projects are so much bigger,” says Crawford. His company has completed numerous projects for federal buildings, military bases, universities, hospitals, and private business across the US and Canada.

In some cases, Leadership in Energy and Environmental Design (LEED) certification has opened doors to suppliers of these systems. “Even though LEED costs have gone up and a lot of people have gotten away from LEED certification,” he adds, “it presents a format for people to do things the right way and in a sustainable way. So that has helped a bit.

“Even in facilities where the owner chooses not to pay for LEED certification, they still like to look at doing things in the best possible way. We’ve done jails, laundries, all kinds of commercial facilities. It’s a no-brainer—when 70 to 80% of our water use is nonpotable, why are we spending this money on energy to clean up the water, to get it to a potable status, plus all the money it costs to pump water out and back from centralized municipalities? Decentralized water systems are going to be the trend of the future.”

Crawford states that these rainwater harvesting systems can significantly reduce stormwater runoff. “It will be the trend. It will be the norm. It will be demanded on all new construction in the future, without a doubt, as it has played out in Europe.

“What most people don’t realize,” he continues, “is that for every 1,000 square feet of roof that you collect water off of, you’re going to average 620 gallons for an inch of rainfall. If you have a 2,000-square-foot house in Virginia, you’re looking at over 40,000 gallons of water a year.

“Or in Oregon or Washington state, there’s a huge amount of water coming off of these roofs. In Texas, where water’s extremely expensive, and also scarce, why would you not collect all the water off your roof?”

Photo: Rainwater Solutions

Crawford adds that once the rainwater has been collected, it can readily be connected to a home irrigation system. “That’s very easily done. We have plug-and-play systems we ship all over the country. They can be off the truck and in the ground in 30 minutes, once the hole is dug. You simply just hook that up to your supply pipe for your irrigation system and transfer it over.

“One of the things you’re going to see in the irrigation industry is a complete makeover and a change in what type of irrigation systems are being put in. You’re going to see subsurface systems put in, smarter controls put in, rain gauges and moisture sensors put in to your zones. People waste and overwater tremendously. There’s a huge amount of waste in that industry.

“The problem is that, in the US, we don’t pay the cost of our water. Most of it is taxpayer subsidized, so you might be paying 25 cents on the dollar. If everyone truly paid the real cost of the water, they’d be much more conservative with it.”

Most rainwater harvesting systems collect rain from rooftops and gutters, and the makeup of the roof is fundamental to how much water is collected, as well as to the quality of the water. “If you’ve got a membrane roof, that’s going to shed it off,” says Crawford. “If you have an old tar and asphalt gravel roof, that’s going to collect much less water. A lot of it is going to stick on there and sit on it.” Not to mention the dust and dirt and sediment that will accumulate on the roof and in the gutters.

As a result, a variety of filters and disinfection systems are available to bring the water to acceptable levels of quality. Crawford’s units contain vertical filters that remove items down to 280 microns. And he notes that a trend in the US is to use ultraviolet light for disinfection.

Crawford is finding that for some people, having a private, protected source of water is a motivation for installing rainwater harvesting systems. “We’ve done schools that use that for a backup supply, so everyone in the community can go to the school and have 250,000 gallons of water, if in fact a hurricane came through and contaminated their water supply.

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