Imagine a natural resource, one that is so precious that people—or, for that matter, any living thing—literally can’t live without it. One that is so coveted that, at times, wars have been fought over it.

Now imagine that this precious natural resource literally falls from the sky on a regular basis. Yet still, much of it goes down the drain.

If you’ve guessed that this resource is water, you’re right; specifically, rainwater. Now that drought has become a way of life in many parts of our country, harvesting rainwater is gaining a higher profile.

There’s nothing new about this, really. People have been collecting rainwater for thousands of years. The ancient Babylonians did it.

As someone in the business of providing water to landscapes, the time may have come for you to start doing it, too. If you attended the last Irrigation Association show in Phoenix, Arizona, you would have seen a record number of booths devoted to rainwater-harvesting equipment. This technology’s moment has come.

rainwater harvesting can be as simple as a rain barrel and a hose, or as complex as a network of underground cisterns holding thousands of gallons, connected to pumps and filters.

“Any type of system that collects rain is rainwater harvesting,” said rick Scaffidi, vice president of sales and estimating at Millersville, Maryland-based Environmental Quality resources, Inc., a company that builds rainwater recapture systems. “It can involve permeable pavers, such as you’d find on a parking lot, rain gardens, bioswales and gravel wetlands. There are a whole host of things that capture, hold and infiltrate water.”

Chris Maxwell-Gaines and his partner Blake West are co-owners of Austin, Texas-based Innovative Water Solutions, LLC. The two Texas A&M alums met when they were both doing stints in the Peace Corps in Surinam, where they experienced what it was like to have no access to running water. “It opened our eyes to the value of water,” said Maxwell-Gaines.

Returning to Texas, they settled in the Austin area, and for the past ten years, have been building rainwater and gray water systems, eventually becoming licensed irrigation contractors.

In contrast, Brian Perwak, president of Corbett Irrigation, Inc. in Acton, Massachusetts, was already a veteran irrigation contractor when he started looking into rainwater harvesting.

“We got involved with it because we recognized the need for sustainability in our industry,” said Perwak. “Irrigation is at the top of the chopping block when it comes to environmental impact and how water usage is viewed.”

While Massachusetts isn’t a drought state, Perwak says that water is nonetheless becoming a more prominent issue there. Some communities are becoming more aggressive about watering bans, and in some cases, not allowing irrigation systems to be installed, period.

He feels that irrigators should not only keep striving to make their systems more efficient, but should also look at alternative ways of supplying those systems, in order to keep landscape irrigation in a positive light.

Types of systems Neal Shapiro is secretary of the American rainwater Catchment Systems Association (ArCSA) in Tempe, Arizona. He’s also the watershed management program coordinator for the city of Santa Monica, California’s Office of Sustainability and the Environment.

“There are two strategies to harvesting rainwater, ‘passive’ and ‘active,’” he said. “A passive system uses soil ecology to filter out low levels of pollutants.” Bioswales, rain gardens and rain barrels are examples of passive systems. Gravity makes the collected water flow.

An active system requires a pump. Rainwater is collected into rain barrels, cisterns or tanks, either above- or below-ground, then pumped out to an irrigation or plumbing system, to be used on the landscape, or for toilet flushing and laundry.

A potable system is the most complex of all. A lot of multi-stage filtering is needed before rainwater becomes safe to drink. Such a system is much more expensive, as you’re essentially building a mini water-treatment plant. But most rainwater is harvested so that potable water isn’t used for landscape.

For residences, Maxwell-Gaines’ company usually installs 3,000- to 12,000-gallon systems. The smaller tanks work well on homes within the city. The price goes up with choice of tank and materials—polyethylene, galvanized metal or galvanized metal with a poly lining.

Tanks are usually installed in backyards or beside a house. The existing water spouts are converted to watertight PVC-type downspouts, which are then connected to an underground pipe which feeds the tank.

“Essentially, we create a ‘p-trap,’ like the one under a kitchen sink,” said Maxwell-Gaines. “The person’s home looks like they have conventional downspouts. Someone passing by wouldn’t even know that the house is collecting rainwater.”

Mike Garcia, owner of Enviroscape LA Landscaping in Manhattan Beach, California, is a landscape design contractor and a certified pond builder. He takes a different approach, building underground water storage structures using “the same basic infrastructure as pondless waterfalls.”

This is his technique: he first digs a big hole, puts in underlayment, and then puts pond liner over it. The hole is then filled with poly tanks that look like milk crates. These are stacked, and layers of gravel and geotextile fabric are placed on top of them, then another layer of gravel on top of that. The tanks are then connected to a pump.

An important component to any type of rainwater system is a “first flush” diverter. The first flush is the first few minutes of rainwater at the very beginning of a storm, and the dirtiest—full of pollutants, sediment and debris.

The diverter channels this water either to the landscape or directly to the sewer system, away from the tank. If rain continues beyond that point, the sponge-like device inside the diverter fills up, and the rest of the water goes into the tank.

Garcia likes to use this first flush on the landscape. “After all, people buy chicken poo to fertilize with,” he says. “That first flush, with all the bird stuff in it, is great for your garden.”

If you’re using the water just for irrigation, you’ll still need to filter out small particles, as they’ll clog the pumps and valves, as well as the spray heads and/or drip emitters.

The underground-tank approach works well in new construction; the above-ground approach is more adaptable to retrofits. In cold climates, you’ll need to put tanks far enough underground so they won’t freeze. Above-ground tanks will have to be drained before winter hits.

Another important component is an auto-fill system, using municipal water as a backup for when a tank’s level falls too low. The auto-fill system should be automatic, so the system owner never has to ask, “Do I need to turn on any valves?”

These systems can now be hooked up to smart controllers that can manage both the irrigation and the rainwater harvesting system. “We’ve taken a basic smart irrigation controller, and made it so it can interact with rain harvesting sensors, tank-level floats, UV sterilizing lights and filters, in addition to weather stations and soil moisture sensors,” said Larry Sarver, president of Tucor, Inc., Wexford, Pennsylvania.

Depending on the input they receive, these controllers can stop or pause irrigation, pull water from a potable source, a third source, or multiple sources. Some can send email alarms when a flushing action or a portable water backup is needed.

Who are the customers?

Perwak has found a great client base in the Boston area’s many colleges and universities. “These campuses are so well-landscaped and manicured, they’re huge water users,” he said. “At the same time, they’re very active in trying to be greener in their every use of energy.” Boston’s municipal water is also very pricey.

Austin’s progressively-minded population is the reason Maxwell- Gaines and his partner chose it as the launching pad for their business.

“Austin is the Mecca for rainwater harvesting,” he said. The city began giving away rain barrels back in the early ’90s.

Most of their urban residential customers want to reduce their environmental footprints. “They already drive Priuses, and this is kind of the next deal for them.” It doesn’t hurt, either, that the city has a great rebate program. residents can get up to $5,000 for installing rainwater an easy sell for homeowners who are capture systems. This makes them “on the fence.”

On the commercial side, 95 percent of the partners’ work is new construction. Although rainwater engineer out” when there are cost systems can be “very easy to value- overruns, it helps that most developers feel the need for LEED. “When they want that silver or gold rating, is going to go forward,” said you can be pretty sure that a project Maxwell-Gaines.

“We’re lucky that central Texas has a very healthy development climate, with lots of large-acreage homes being built. A lot of them are in places where there is no municipal water supply. You either have to drill a well, or install a rainwater collection system.” Some of the systems he’s built have 50,000-gallon tanks.

In another part of Texas, the Dallas/Fort Worth metroplex, rainwater harvesting started long before the drought. “So much of our groundwater is not usable for irrigation because it’s so salty,” said Dotty Woodson, extension program specialist, water resources, at Texas A&M’s AgriLife Extension Service in Dallas.

“It’s very expensive to dig wells and keep filtering that sodium and calcium, so rainwater harvesting seems like a pretty good alternative.”

She adds that in the entire state of Texas, everything purchased for rainwater collection is sales tax exempt— gutters, downspouts, cisterns, pipes. Plus, “every state building has to have a rainwater collection system.”

Can rainwater harvesting “make it rain?”

All the contractors we spoke with say that rainwater collection collects some nice profits, too. LEED points, drought, government regulations and incentives all work together to make it a lucrative endeavor.

Scaffidi says his business is brisk, thanks to the U.S. Environmental Protection Agency (EPA). “They’ve regulated that everybody has to meet their TMDL (total maximum daily load) limits for pollutants in water, based on population. So, many cities and counties—at least here in Maryland—are having to retrofit significant amounts of their infrastructures with rainwater systems.”

Maxwell-Gaines says that the extreme Texas drought, combined with an economic boom, created a “perfect storm” that got people thinking about the future water needs of a fast-growing population. That’s really helped their business. “Every year, we’ve increased revenue. This year, in particular, has been a banner one, with a 25 percent increase over last year, and the market’s still growing.”

Maxwell-Gaines and his partner now find themselves doing landscape design and installation as a natural outgrowth of their core business. “We’re calling it ‘re-landscaping,’ and we’re doing it so we can offer customers a complete package. Because of the drought, people are saying, ‘I need to use less water.’ So, we’ll take them from very water-thirsty landscapes to very drought-tolerant, low-water-use ones.”

Do rainwater and rotors mix?

Suppose a customer already has a conventional irrigation system with sprinklers and/or rotors. Can that system be retrofitted to use rainwater?

Of course, says Maxwell-Gaines, although he concedes that for maximum efficiency, it would be best to install a subsurface drip system. “But many people already have irrigation systems, and don’t want to redo the whole thing. We’ve done that countless numbers of times on our retrofits.”

Garcia, on the other hand, says no. “A regular sprinkler system is extremely inefficient. A rainwater harvesting system only makes sense if you’re going to use drip irrigation with it.”

“As it is, half my jobs these days are converting conventional overhead spray heads to drip irrigation. The rainwater capture systems are the upsells of those conversions.”

Can my customers afford it?

You may be wondering if rainwater harvesting is affordable for a customer with a modest income and tract home. Maxwell-Gaines says he gets that question all the time—and the answer is yes.

You and the customer have to look at the end use for the rainwater. Does he just want to hand-water some patio plants? Then, a 300- to 500-gallon tank will do. If he wants to connect it to his irrigation system, however, he’ll need a bigger tank.

“Whatever amount they want to invest, there’s a rainwater system that can be sized for that budget. That’s the great thing about it.”

Learning about it If you’ve decided to become educated about rainwater harvesting, there are plenty of resources out there. Classes are available through the Irrigation Association. ARCSA offers many two-day workshops for those seeking to pass their Accredited Professional exam. The workshops cover the basics of rainwater harvesting, both active and passive, plus design and installation for residential as well as larger commercial systems, plus other topics.

In Texas, Woodson teaches rainwater certification classes based on ARCSA’s program. Ultimately, she’d like to see a rainwater licensing test as tough as the state’s irrigation license test, in order to protect the public. (Texas’ test is known to be one of the toughest in the U.S. Half the contractors who take it fail the first time.)

Woodson is particularly worried about cross-contamination with potable water, and wants the public to have assurance that the people installing rainwater systems are trained. “right now, anyone can come out and say, ‘I can set you up with rainwater catchment.’ But do they really know what they’re doing? Do they understand filtration, backflow, overflow?” Should you consider getting involved with rainwater harvesting? If you ask Mike Garcia, the answer is yes. “Water used to be sold like things you buy at Costco, where you bought it in bulk and got a cheaper price. Those days are gone forever.”

“Rainwater harvesting is here to stay. Irrigation contractors need to get familiar with this, because if they don’t learn the technology, somebody else will.”