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Rainwater Harvesting

Jason Gibby | Eco-Green Sustainable Landscapes

What's the catch?

“Raindrops keep falling on my head” is the opening line of a popular song, but you can bet Burt Bacharach would be singing a different tune if those raindrops were falling inside his home. A ceiling leak can be more than a little annoying. If left unchecked, water will pour down from the ceiling and make a terrible mess. So like most people, if you saw water dripping down, you’d probably grab a pot and place it beneath the leak to capture some of that water.

When rainwater falls on your roof, it’s just like that leak. If you do nothing to stop or capture the water, it’ll either make a mess or become waste. Either way, better options exist to deal with the problem. How can you recapture that water and use it for another, much better purpose? If you’re in one of the many parts of the country that regularly experiences drought, then you’ve probably already asked yourself that question.

However, water conservation should be on everybody’s mind, because there’s more to it than just the drought. We know there are limited water sources available and no new sources have been discovered. As our population grows, more people are tapping the same sources.

What does that mean? It means that we’re now taking more water from our reservoirs and lakes than we’re able to replace. This is magnified even further by the many states now experiencing drought conditions. While there are other ways to re-use water, let’s focus on harvesting rainwater.

Capturing rainwater isn’t a new idea. The Romans funneled rain to underground cisterns, and Thomas Jefferson harvested rainwater to brew his beer. Now, years later, we’re interested in this same system, but our interest is more of necessity than curiosity.

“More and more people are considering rainwater harvesting,” says Michael Nelson, founder of Ecoscapes in Sante Fe, New Mexico.

“The penalties for using vast amounts of water are prohibitive, which makes it more attractive to collect and store rainwater. And, as the price of water goes up, it’s beginning to get easier to show how you get your money back in the long haul.”

While many options exist for capturing and storing rainwater, two stand out as clear frontrunners. The first is fairly straightforward, like the pot. A rain barrel or tank is installed on the property, and as rain falls, it’s captured and stored.

“With above-ground tanks, it’s pretty basic,” says Jeff Helton of Bushman USA, Temecula, California. “The unit sits on a gravel base, so you need to have at least one rain gutter. The system could be as simple as putting the downspout into the top of the tank and letting it fill up.”

Under normal circumstances, this water would gush out and spill onto the property, becoming wasted runoff. But with a water catchment system, you simply attach the downspouts to the rain barrel, and voilà, water that would normally wash straight down the drain becomes yours to use.

For simplicity, this setup would be a good choice. To paraphrase John Lennon’s “Across the Universe,” it’s like rain into a paper cup: easy, undemanding and practical. Rain barrels collect water as it falls and then save the surplus for dry spells. But if you’re looking to give the yard a facelift, you might consider the underground option. That is to say, although some rain barrel setups utilize an underground tank, most are above ground.

The second option allows you to hide the system underground, providing even more storage space.

Imagine the ceiling leak again, except instead of a pot, think of a floor that’s capable of absorbing all of that water. This setup, often referred to as a modular underground catchment system, is much like that.

Called modular systems for short, these units are fairly straightforward and are extremely effective at capturing and storing your rainwater. They still require a storage device, but it’s not quite as simple as putting a pot under the leak, so to speak.

Instead of a rain barrel, a modular system uses many mini storage devices or modules, also called water blocks, to capture and store the water. “Each one of them holds about thirty gallons of water,” says Ed Beaulieu, chief sustainability officer of Aquascape in St. Charles, Illinois. “We can put them together in different configurations. So we could use infinite variations on the volume of water, depending upon the projects.” These water blocks, just like the first option, then store the water for irrigation or other nonpotable use.

The blocks or cubes are generally manufactured from recycled plastics and designed with an interlocking capability. After digging a wide, shallow hole, a lining is placed over the ground surface to ensure that no water is lost. The hole is then filled with the interlocking cubes, which are placed on top of the lining, and when it rains, water fills these cubes. Once the cubes are placed, permeable pavers, planks or soil go over the top to make the area useable and aesthetically pleasing.

“On the consumer end, I’m seeing a lot of people who are willing to pay the extra money to have a rainwater system installed because they want to be more self-sustaining,” says Beaulieu. “This allows them to capture and re-use the water onsite.

And since this water can’t be restricted—except for drinking—once you have it stored underground, you can use it as you see fit.”

If you’re not interested in permeable pavers, the modular systems can use a series of pre-filters or catchment areas instead. These catchment areas are simply small reservoirs that store rainwater. After each rainfall, the water is then routed from the catchment area through an underground piping system. Of course, like the other units, the catchment area can eventually guide the rain into the property’s irrigation system, which then makes that new source of water fully usable.

Determining which system might work for you can be difficult, especially when they both perform the same duty—recapturing water. But receives about eight inches of annual rainfall. Catchment systems capture, on average, 600 gallons for every inch of precipitation on 1,000 square feet of roof.

So with eight inches of annual rainfall, that 3,000-square-foot property could harvest about 14,500 gallons annually. In St. Louis, Missouri, then, which sees about 40 inches annually, a harvester could capture more than 72,000 gallons on a similarly sized building. And those numbers are on smaller, likely residential properties. Bump that up to a commercial, 100,000-square-foot building, and the number jumps to about 2.4 million gallons.

Beyond just capturing and preserving water, these systems also prevent harmful runoff in regions that regularly experience major storms. When rain falls onto hard surfaces, it runs off onto land. In between rainfalls, pesticides, hydrocarbons, fertilizers and other impurities build up in the soil.

After a major rain, the rainwater rinses these contaminants from the ground. And because of this cleansing ability, water is known as the universal solvent. Unfortunately, with its ability to flush impurities from the land, water unintentionally pollutes our waterways and sewage systems. With nowhere else to go, the excess water runs straight into these facilities.

Due to the overwhelming presence of hazardous chemicals, water and sewage treatment plants label water as a ‘waste product’ and eliminate it as quickly as possible. Since we can’t manufacture water, we definitely don’t want to dispose of it. So finding a way to capture it before it can flood our drains and waterways becomes a matter of urgency.

“Harvesting units hold this water until the storm event has passed,” says Paul James, founder of Just Water Savers USA in Ballinger, Texas. “And then hopefully, within the next few days or weeks, that water can either be used onsite or gradually allowed to go into the drain system.”

Some regions have mandated rain catchment systems to ensure water detention.

The alternative, losing hundreds of thousands of gallons of water after every storm, is simply not being green. New housing and commercial developments in these areas must install rainwater storage units or face fairly severe penalties. “A lot of areas now require developments to pay a stormwater discharge fee if they don’t comply,” says James.

Other areas have provided rebates instead. For example, the Metropolitan Water District of Southern California, one of the largest water districts in the country, recently launched a rain barrel rebate program, due to high public demand. In these districts, residences, businesses, industry, institutions and other large landscaped facilities can all receive money back for their investments in rainwater catchment systems.

Whether it’s a drought or a storm, a mandate or a rebate, it’s clear that many municipalities are adopting rainwater catchment as a legitimate option for water storage and management. “We’re going to turn it from a liability into an asset,” says Beaulieu. “Once you can capture it, you can filter it and you can re-use it. So we’re winning on two different fronts: stormwater management on one side, and then using the water as a resource for irrigation or whatever you want to do with it on the other.”

Harvesting rainwater is cost-effective and allows contractors and property owners to reclaim some of their lost self-sufficiency by making use of what’s already there: an abundance of rainwater. Adjusting in hard times, especially during drought, might present a challenge, but those who adapt are often the same ones who flourish. Perhaps Wallace Stevens said it best: “Human nature is like water. It takes the shape of its container.” So, no matter how you choose to capture rainwater, it’s probably good to make sure you have the right pot.

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05.30.2014 at 11:01 Reply

One thing to keep in mind is that some states have restrictions on rainwater harvesting. Here in Colorado, unless you fall into very specific and narrow qualifications, rainwater harvesting is illegal due to water rights downstream. Make sure you know your local laws regarding rainwater harvesting.