Rainwater Harvesting

A growing industry with some challenges ahead


Editor’s Note: This article first appeared in the March/April 2013 issue of Stormwater.

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.

Rainwater barrels

Credit: Rainwater Solutions

“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?”

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.

“Another guy put in what we call a blind insert for his pre-filters, so when the Japan nuclear disaster happened, and we started picking up radioactivity in the US, he actually put in the blind insert and sealed his system off at his house. He runs a big company that supplies X-ray units to hospitals, so he knows all about radiation. He wanted to have his own secure water supply, free of contamination.”

Rain Check in Philadelphia
“ECA [Energy Coordinating Agency] has been around for about thirty years,” notes Zachary Popkin, program manager for ECA in Philadelphia. “It was founded in the 1980s as a nonprofit organization that focused on energy efficiency and weatherization.

“In the past few years, as the issues with stormwater management have increased in the city of Philadelphia, we have started to get into stormwater management. One of the things that we did in our facility was to install a rainwater harvesting system that includes a 3,000-gallon cistern, and we use it for the toilets and urinals in our training center, and also to wash our vehicle fleet.

“When we saw the payback that we got on that, the return on investment, it was quite remarkable. So after realizing how cost effective it was for us, we thought that it would be a good opportunity to enter the market in Philadelphia.”

ECA has been working with the Philadelphia Water Department on two different programs. “One is their rain barrel program,” says Popkin. “Through the rain barrel program, they give out free rain barrels to Philadelphia residents.” Interested residents attend an ECA workshop, where they are provided with installation and maintenance instructions. To date, nearly 3,000 of these free rain barrels have been handed out.

“The other program that we’re running for the water department, which is the program that I manage directly, is called Rain Check,” says Popkin. “It’s in its pilot phase, and that is the water department’s residential stormwater management program.”

The Rain Check program has trained two groups of contractors. One group performs stormwater site assessments for homeowners, to identify what can be done to reduce stormwater runoff. The other group performs the actual installation. These services are heavily subsidized, “to the tune of about 80 to 90%,” states Popkin.

Five “green tools” are offered as part of this Rain Check program. Residential properties may benefit from downspout planter boxes, rain gardens, de-paving of impervious surfaces, porous pavers, and yard trees.

“Although homeowners don’t get a reduction in their stormwater fee for participating,” notes Popkin, “they do get these different installations at a very drastically reduced cost.”

The current pilot program is slated to run through June 2013, although Popkin is optimistic that the city will not only continue the program, but expand it.

“The biggest hurdle at this point is getting folks involved. We have about 250 to 260 participants who have signed on for the pilot phase, and we have about 100 or so that are on our waiting list, if and when the program expands.”

He notes that although the rain barrel program offers the potential for reuse of captured rainwater, the various Rain Check installations are solely intended to reduce stormwater runoff.

“Sometimes an individual site’s conditions might allow for reuse. For example, if we were installing a downspout planter, in certain cases the overflow drain from the downspout planter might be directed toward a plantable area. But for the most part, the goal of these tools is just to reduce runoff, not really to provide water for any usable purpose.”

Nevertheless, Popkin identifies an added benefit to these planter boxes. “The big plus of these planters over the rain barrels is that they’re lower maintenance—because a rain barrel, to be truly effective, needs to be emptied between rain events. When folks neglect or forget to empty their rain barrel, it loses its effectiveness entirely.

“These planters are all planted with drought-tolerant native adapted species, which do a great job of absorbing and filtering that stormwater. Then we have an overflow drain and an underdrain in those planter boxes, which allow the water to escape the box and not become trapped in there. So it’s lower maintenance. They don’t need to be treated after every rain event. The plants and the planting medium do the job for you.”

For homeowners who choose to take advantage of collected rainwater in their rain barrels, there are a number of potential uses. “The rain barrel typically has a screen filter at the top, to prevent leaves and large bits of sediment from entering the rain barrel, but there’s no high-tech filtration system,” says Popkin. “For that reason, we suggest that the water from rain barrels is suitable for using for things like watering house plants, rinsing off patio furniture, or washing a car.

“But we advise against using it to water edible vegetation because of whatever sediment or contamination the water might pick up from the roof. I’m not sure that it would be extremely harmful, but we err on the side of caution, so we recommend that folks not use any harvested water to water their edibles.”

The rain barrels can certainly assist with reducing stormwater runoff, although Popkin noted that they typically hold only about 55 gallons, which will fill up pretty quickly in a typical rainstorm.

There is also a program for nonresidential property owners, known as the Stormwater Management Incentives Program. Administered by the Water Department and a local economic development group, it offers various grant and loan programs for businesses to reduce their stormwater footprint, but to date it has been underutilized, Popkin says.

“But the whole stormwater feeling in the city is gaining momentum, so we think when they do their second wave of grants and loans, that there will be a lot more interest,” he notes.

“Property owners [both residential and nonresidential] are starting to realize how much the stormwater fee is costing them. They’re starting to realize that they need to do something about it. They’re also starting to realize that it’s really not that difficult to do something about it. A lot of these installations are low impact; they’re pretty easy to install and they can do a great job of managing stormwater. I only foresee the demand escalating.”

Rainwater Harvesting in the Southeast
“When you’re talking about rainwater harvesting, you’re either talking about active or passive systems,” explains Mike Ruck of Rain Water Solutions, based in Raleigh, NC. “We predominantly deal with active systems, which means physical tanks, filters, pumps, that kind of thing. When you’re talking about passive systems, that’s when you’re talking about rain gardens, swales, and so on that are designed to slow the water from leaving the site—keeping it onsite so that you get deep ground infiltration, as opposed to just running off and hitting a stream. There are not enough of these systems in place, so streams are becoming less healthy, because we’re sending all that water to the stream rather than mimicking what happened predevelopment. Predevelopment, the majority of the water would stay onsite.

Ruck agrees with others in the industry that rainwater harvesting can both reduce stormwater runoff and decrease potable water demand.

“If you can help offset potable water use, to flush a toilet, then you’re addressing the stormwater issue,” he says, “because you’re storing it and not letting it leave your site. Then when you’re using that water to flush a toilet, you’re offsetting your potable water. There’s not a negative in that equation.”

As an example, Ruck points to a recent project he completed for the nearby Goodwill Community Foundation. “We set up a rainwater harvesting system to provide water for a memorial garden and a commercial greenhouse to grow food for the local community. This system has 136,000 gallons of capacity. They get 12,000 gallons of water for each inch of rain. In North Carolina, we get three to four inches of rain a month, so we’re able to meet a very large portion of their water demand.”

Ruck has found that for residential uses, despite its many benefits, rainwater harvesting may lack a quick payoff for homeowners.

“One of the hurdles we encounter is that water is kept artificially cheap. Municipalities and water providers and utilities don’t necessarily have to make money, and it’s a political hot button to raise water rates.

“If you look at Raleigh, with our growth rate and the water resources that we have, we’re set to run out of water by 2050. But they don’t want to raise rates because next door water is so cheap, so water is a really tricky subject.

“In a water-rich area like the Southeast, we’re used to just turning on the tap and having unlimited water. That’s a challenge for us, because tanks are expensive, pumps are expensive. People ask why they should spend $100 on a rain barrel, when that same $100 might buy 6,000 to 7,000 gallons of water.

“There might not necessarily be a dollar amount payback on a residential system,” he continues. “When you start getting on the commercial side, and you look at stormwater credits and how much potable water you can offset, then you can really look at a return on investment that makes sense.

“With a homeowner, you might be talking about 15 years to recoup the cost, but people live in a house seven to eight years, on average.

“The other challenges are just education. People think, ‘It’s rainwater from the roof; it’s dirty.’ But when you can control where it hits, and filter it, it can be used because it’s relatively clean coming out of the atmosphere.

“Probably 85% of the houses in America have asphalt shingle roofs. Most commercial properties have some type of metal roof or some type of membrane roof. The slicker the surface, the better your water quality is going to be coming out of your downspouts. The asphalt shingles are fine for collecting water for use in the garden, but asphalt shingles are going to hold a lot more dust, pollen, and particulates. But for a roof with a slicker surface, these won’t stick to it, it will just blow off with the next breeze.”

Exponential Growth
Jim Harrington runs Rainwater Collection Solutions in Alpharetta, GA. His company produces The Original Rainwater Pillow, which he describes as “a flexible pillow that fills up and empties with water; it moves up and down. It’s horizontal storage.

“I can make a pillow any footprint you want, from 1,000 to 200,000 gallons. We have residential and commercial applications. It normally goes into wasted space under a deck, in a crawl space, or under a porch.”

Harrington is very bullish on the rainwater harvesting industry, and notes that it has been growing exponentially. “It’s been huge,” he says. “It started out from nothing. There was a study about new products in rainwater harvesting that showed there is a new product coming out every month, on average, about 15 new products a year. It’s growing like crazy. We’re running out of water. That is a fact that’s pretty much undeniable.

“We’re literally—slowly, but surely—running out of water that’s clean and usable. Not only that, but energy is so huge. Probably 40 to 60% of the cost of water is attributed to the energy to move the water from one location to another.

“You cannot have energy without a lot of water, and you cannot have water without a lot of energy. We talk about energy and read about energy all the time, but we don’t talk about the fact that probably 60% of the water that we use in the United States is used to create energy, for cooling towers and hydroelectric power. You’re talking about billions of gallons a day.

“But pollution is really our biggest problem. One day, EPA is going to come down on Atlanta and say, ‘The river’s too dirty.’ We can’t afford to redo all the sewer systems, so the only way we’re going to go ahead and control the stormwater runoff in a reasonable way is to make all the homeowners do rainwater harvesting.”

A Canadian Perspective
Mike Gregory, a senior water resources engineer with AECOM, in Kitchener, ON, is very upbeat about the potential for rainwater harvesting, although he is dismayed at the slow progress the industry is making.

“It reminds me of LID [low-impact development] maybe five years ago,” says Gregory. “It’s a great idea, and it works on individual sites, individual lots, individual parcels. But for big applications, I don’t think we’re there yet. That doesn’t mean we stop the dialogue. We have to keep going.

“What is so exciting to me is that it’s better than LID. It’s LID plus. LID doesn’t work in locations where you just don’t have good groundwater conditions or soil conditions. It’s not for everyone. But there is always, always, always an opportunity for reuse on a site.

“Once you have storage, you can use it again. One of the downsides of things is that we’re just not there yet with the treatment aspect. There are clean sources of runoff, and there are dirty sources of runoff. There are some you don’t want to touch, while others are perfectly amenable to reuse.”

As in the US, Gregory says, there can be difficulty with the plumbing codes. “There is a plumbing code that applies to individual property, at least here in this part of Canada. When it spans multiple sites, then it comes under the jurisdiction of a state or provincial authority, and that gets difficult to permit. They don’t know what to do with it yet. They don’t know how to classify it, and that’s where it gets difficult.”

But for individual properties, he reports some good activity. “We’re seeing in bigger cities that have lots of LEED applications; they’re washing their vehicles and equipment with this water onsite. And there are some academic institutions that are kind of showing off with what they can do.”

As others have noted, Gregory also reports that a number of homeowners with rain barrels prefer to keep them filled, in anticipation of drought conditions. “As a stormwater management thing, that’s a no-no. You have to empty them before the storm comes.” He says that for larger systems—in strip malls, for example—the units are automated, which resolves this problem.

Gregory also addresses the issue of how to make use of rainwater harvesting in arid regions where there may be extended drought conditions. “That is where I think aquifer storage and recovery operations come in, like perhaps in Texas or Arizona. If you have the right aquifer conditions, you take the runoff and store it in the ground. Then when you need it, like in a drought period, you can just pump it on up. In places like India, I think they that. But there’s a cost to that, of course.”

Gregory reports some municipalities taking positive steps toward reasonable reuse of collected rainwater. “Slowly but surely, it’s encouraging to see places like transit commissions in big cities moving toward washing vehicles with stormwater. That’s a no-brainer. You don’t need high quality water for that. It’s not going as fast as I’d like it to, though.

“Another reason things aren’t going as fast as they might is that the payback period is just not tipping the scale,” at least for residential properties. Gregory notes, however, that for large public works facilities, payback shouldn’t be an issue.

“They have ample rooftops, and presumably clean parking areas. They can collect the water and wash their trucks, and use the water for construction projects and irrigation, whether onsite or just for water trucks for where they’re needed. That seems like an easy application.”

He also reports that LEED credits have been a help in getting commercial properties on board. “For the couple projects that I have been involved with, LEED was driving it. It is an important driver. We can claim some credits under the stormwater part. So on one project we had a green roof and a greywater system that did claim some credits. Absolutely, that is helping.”

While noting that such efforts can significantly reduce stormwater runoff, Gregory advises that rainwater harvesting is not a panacea. “It will never, ever replace the risk for flood control benefits, for the big storm events.

“You’re going to get those strong, intense rain events where everything is bypassing things, and flood control should be a city’s biggest priority—for both property and lives. LID and rainwater reuse is not going to help those types of things. But I am impressed what volume reduction you can get from these small facilities in large numbers.”

Bureaucracy, however, remains a problem. “We were involved in a study for a local government here,” says Gregory, “to look at how reuse fits into their policies and procedures, and that has just gone nowhere, in three years. It’s just so frustrating.

“We have cheap water here in Canada, let’s face it. We have a lot, which means we waste it. So that’s frustrating. I put a lot of my hope in treatment technologies.”

Gregory is of the opinion that once more efficient methods of treatment are available, both for stormwater and rainwater, the industry will grow as it needs to. “Despite my negative opinion that it’s not happening fast enough, it’s so exciting,” he adds. “I’ve been in stormwater for 22 years now, and this is a great time to be a stormwater engineer.”

  • Robert Moore.

    As an ARCSA accredited RWH professional; Master Organic Gardener; Aerobic Microbiologist/Researcher; Master Composter and Texas RainCatcher of the Year (2009), would like ‘pipe in’ with some thoughts…
    First, about asphalt shingle roofing. While water is a ‘universal’ solvent (especially under rainfall force), so will continue to degrade such roofing over time, from my research (and others – contact shingle manufacturers), the process is quite slow after the first year and even in the first year of installation is insufficient to cause concern for watering vegetable crops whether in-ground or in planter media due to in situ aerobic microbiological activity capable of dealing with such compounds. Such caution not to water edibles via RWH is not based on science.
    Second, it’s been my experience that those who ‘issue/sell’ RWH catchment barrels do not provide adequate printed/electronic information for homeowners to effectively install/utilize them (such as how to connect multiple barrels; the need/reasons to soon utilize collected water and the many mechanical options (and places to put it) regarding means to utilize the water for a variety of applications.
    ARCSA should be more proactive in that area on their website, particularly to encourage use of such water to facilitate dual home composting bins (next to a rainbarrels) that incorporate leachate collection, as it contains no treatment chemicals damaging to plant microbiology. And such leachate from a mature compost pile is pure nature-made immediately-available (foliar & root drench) plant food produced by microbial activity.
    Third, regarding stormwater abatement, there’s a LOT more water falling on home roofs/property than there are commercial roofs, even considering parking lots. Which means that residential roof/property runoff is a singular major issue, and in my opinion, activity needs to be directed toward homeowner/neighborhood associations. Not just for education, but to develop methods and means to conserve water in ways that a subdivision developer did not consider. Am not suggesting that such organizations become taxing agents, but rather a resource for local community action to become more involved with municipal stormwater agencies in promoting catchment and containment opportunities.
    Fourth, municipal stormwater agencies should ‘partner’ with land grant universities to promote RWH stormwater abatement practices through their Extension Services to facilitate public education and activity.

  • Robert M. Alvey, P.G..

    Good article on an important topic. The EPA began a WaterSense program in 2006. Allows a system for certification, somewhat similar to the LEED.

  • “The current pilot program is slated to run through June 2013”. It’s currently 2016, was there no update on how the pilot program went?

    • Zach Popkin.

      So I did this interview a long time before the article was published. The program is no longer functioning as pilot. We’ve merged the two programs mentioned (Rain Barrel Program merged into Rain Check). Since launching at ECA, the program’s management was taken over by the Pennsylvania Horticultural Society (PHS). We also have a brand new website: http://www.PWDRainCheck.org. You can find my contact info on there. Feel free to reach out with any questions. – Zach


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