Can a Rain Barrel in Every House Help Ease the Water Crisis?
At his home in Tucson, Arizona, Brad Lancaster gets all the water his family needs from a 2,000-gallon cistern that collects storm runoff from his roof. Annual rainfall in Tucson averages 12 inches per year, but with the help of a gray-water recycling setup that reuses bathing and clothes-washing water, Lancaster said his system allows "showering at least once every day, cooking, washing the dishes, doing laundry, and also irrigating a garden and fruit trees."
Lancaster is the author of several books that show how cities and individuals can redesign their built environment to channel rainwater into environmentally productive use. I sought him out because I wanted to know whether rain barrels were a smart approach to water conservation. In my own state of California, rainwater capture for non-potable home use—meaning, basically, for yard watering or other irrigation purposes—has only been legal since 2013. But ever since, municipalities up and down the drought-stricken state have eagerly started enlisting citizens in an effort to ease the load on water utilities. The prospect of ample storms in a historic El Niño winter adds extra juice—in September, the city of San Diego cited the likelihood of an especially wet winter as a great reason to take advantage of a rainwater barrel rebate program.
Throughout the arid West of the United States, water policy makers are waking up to the compelling logic of storm-water capture. We've realized that transforming our cities into impermeable parking lots has turned out to be a profoundly wrongheaded move. In the major coastal metropolitan regions of California, for instance, most rainwater is channeled into storm drains and swiftly swept out to sea instead of nurturing local flora and fauna and recharging aquifers. It doesn't have to be that way: A study by the Pacific Institute concluded in 2014 that storm-water capture in San Francisco and Los Angeles could increase water supplies by as much as 630,000 acre-feet per year, or "approximately as much water as used by the entire city of Los Angeles each year," according to the report from the Oakland, California, nonprofit.
Rebuilding urban infrastructure to capture rainwater, however, will be enormously expensive and time-consuming. The attraction of rain barrels is that hooking one up to the downspout connected to your gutters seems like something that can be accomplished with a trip to Home Depot and an afternoon of work.
In Australia, which suffered through a decade-long "Millennium Drought” that ended in 2010, it is now standard practice in most of the country to require rainwater capture systems in new or remodeled homes. Shouldn't residents of California—and everywhere else where water is increasingly precious, follow suit?
The answer isn't as simple as it seems. On the one hand, rainwater capture systems are a bit more complicated than they appear. In California, they need to be earthquake safe, screened to prevent insect breeding, and algae and UV resistant, for starters.
More troublingly, there are also questions about their overall cost-effectiveness. In February, an influential hydrologist at the University of California, Davis, Jay Lund, published a blog post arguing that based on the average $100 price of a 50-gallon rain barrel, the total cost per acre-foot of water supplied by rain barrels could be "5 to 10 times the cost of desalinating seawater"—which is itself one of the most expensive approaches to boosting water supplies. His implied economic argument: Big infrastructure projects make more sense than a proliferation of rain barrels.
To the people who take rainwater capture seriously, a 50-gallon barrel is hardly worth the trouble. "Anything smaller than 500 gallons is just playing around," said Lancaster, who notes that for every 1,000 square feet of roof, an inch of rain will deliver 625 gallons of water. One good-sized storm, and your 50-gallon barrel will be overflowing in a jiffy.
Albuquerque, New Mexico, resident Mario Herrera knows what Lancaster is talking about. After trying, and failing, to grow a lawn using a minimal amount of water, he became one of nine participants in a city-subsidized rainwater harvesting pilot program administered by the New Mexico Water Collaborative. He ended up getting a 530-gallon cistern that filled up to max capacity in one storm and has provided all the irrigation requirements for his new drought-tolerant front yard ever since.
"I like to do whatever I can to conserve," said Herrera. "And now everything is just thriving."
The tank stands out, he said, "but it's not an eyesore." Rather, it's a conversation starter: "It makes people look and say, 'Hey, what's that?' "
In Australia, the average capacity of rainwater cisterns installed in Sydney to comply with building code regulations was more than1,000 gallons. So I asked Lund if the size of the barrel mattered in his equation, citing the Australian track record. "A 1,000 gallon rain barrel that is filled once annually in a Mediterranean climate in So Cal. will get an average household through about 3–5 days," he replied in an email.
Let's take a closer look at those numbers. The average household in California consumes around 360 gallons a day, a figure that maps more or less accurately to the average Californian consuming 80 to 100 gallons per day. Naturally, if you consume less water, your barrel goes further. (Brad Lancaster said his family gets by on a hard-to-believe five gallons per person per day, but he's probably an outlier.)
There appears to be a connection between taking the effort to install a rain barrel and becoming a more parsimonious consumer of water. That's because rainwater barrels help "shift consciousness," said Laura Allen, the founder of Greywater Action, a California nonprofit that specializes in educating communities on how to install sustainable water systems.
"People are shocked when they watch a barrel fill in just a few minutes in a big rainstorm," she said. "It's very enlightening."
They are equally amazed, she continued, when they see how quickly 50 gallons can disappear when used to water a garden. "It encourages them to think about how they can collect more and how they can use less. A rain barrel is a good starting-off point to think about how we could make a bigger impact in actual water consumption."
Albuquerque's Mario Herrera agrees. Having witnessed the success of his cistern, he is open to going the next step and installing a gray-water reclamation system. "I would totally do it," he said.
There's a clear opportunity for aggressive public policy here. In Tucson, one of the earliest U.S. cities to push rainwater capture, you can now get up to $2,000 to help implement a rainwater harvesting system, said Lancaster. To get the rebate, however, you have to attend a three-hour class "on the basics."
But that's absolutely fine, as far as Lancaster is concerned. What's not to like about a "policy that educates you rather than puts some more demands on you, and ends up with you having a healthier landscape that costs you less money, yet it is more lush and more productive while at the same time benefiting not just yourself but the larger watershed and its community, so you are contributing to the greater good along with your own good"?
This article has been revised to reflect the following correction: An earlier version of this article misstated the spelling of a Albuquerque, New Mexico, resident’s last name. It is Herrera.