Harvesting the Rain: An Old Idea Takes on New Life
As Californians grapple with ways to save water in this third consecutive dry year, Jerry Block has taken an extreme path.
Last month, the retired medical doctor had four gravity-fed, 5,000-gallon polyethylene water tanks installed on his Monte Sereno property. The system will harvest raindrops to provide irrigation for an extensive food garden.
Block sees it as a patriotic as well as an environmental statement.
"Collecting rainwater locally and growing food locally will reduce our dependence on foreign powers," Block says. He spent $24,000 on the 20,000-gallon system, which he calls a long-term investment.
The scale of Block's system is out of reach for most homeowners, but rainwater collection - even on a small scale - is an ancient idea gaining new life. Old-fashioned rain barrels and cisterns are hot items. Vermont-based Gardener's Supply says sales are up at least 30 percent this year, predominantly on orders from the West and South. And some water agencies are offering rebates to offset their cost.
"A rain barrel is a place to start. It's part of people becoming aware of the issue of a finite resource," says Tim Pope, president of the American Rainwater Catchment Systems Association, based in Austin. "Rain harvesting is growing tremendously in the United States, especially in California."
Simple rain barrels made of recycled food-grade plastic or polyethylene that store about 50 gallons of water at a time from roof downspouts can be purchased for as little as $50 at retail outlets and online. There are do-it-yourself videos and instructions on the Internet for building them from plastic drums, wine barrels and even trash cans. To boost capacity, multiple containers can be linked with pipe or hoses and placed in unused spaces, such as along the side of the house.
"If you don't do a lawn, it's surprising how much garden you can have with a relatively small amount of water," Pope says. About 600 gallons of water can be collected for every inch of rainfall on a 1,000-square-foot roof. For tanks catching the runoff from a 2,000-square-foot roof in the Santa Clara Valley - where 15 inches of rainfall annually is the norm - that adds up to 18,000 gallons per year.
"Jerry isn't installing the system to save money, because his water bill will only reduce by about $65 a year for saving 20,000 gallons of rainwater," says Robert Lenney, co-owner of Rain Harvesting Systems, the Northern California company that installed Block's project. "He's doing it to help the Earth by reducing the carbon footprint from the electrical company and the water agency because they won't have to pump that 20,000 gallons of water to his home anymore."
The system also keeps all that water from coursing through water treatment plants as landscape runoff, and it provides an on-site source of water for emergencies such as fires and earthquakes. It can't be used for drinking unless it's treated with ultraviolet light or a reverse osmosis system, and potability rules and standards vary from city to city and county to county.
Lenney's company - and others like it - also install more modest setups. The price, which depends on the size and complexity of the installation, ranges from $7,000 to $10,000. On some sites that aren't sloped like Block's, pumps must be added to deliver water from downspouts to collection tanks.
The key to the system at Block's place is the patented Gutterglove Gutter Guard, invented by Lenney and his business partner John Lewis. The stainless steel mesh filtration device is attached to existing roof gutters and keeps debris - even particles of sand - from gumming up the works. For Block's installation, the downspouts are connected to a network of trenched-in PVC pipes that carry the water downhill, under the rear deck and into the tanks. Once one tank is full, those farther downhill will fill up.
"On this job, the owner calculated how much water he would need for his garden, and we designed the system based on that," Lewis says. "Three-quarters of this roof will capture 30,000 gallons of rainwater a year, based on annual rainfall numbers from 2008."
Block's backyard already has a variety of fruit trees and some small raised beds where he is growing such garden staples as broccoli, sugar snap peas and spinach. But the garden he envisions, adjacent to the water tanks, will be big and bountiful.
"We will put in as much as we can using mounds to plant intensively," Block says. "We're into the whole locavore movement." Paying for the water system was a "sacrifice," he adds, "but it was a lifelong dream." Block also has a 10-kilowatt solar array that supplies all of his home's electrical needs, and then some.
Lenney says rain collecting is gaining traction as water agencies impose drought restrictions. Guy Giordanengo, vice president of the Water Tank Company - the Sonoma County manufacturer of the tanks Lenney uses - says that the last six months have brought "a considerable increase" in interest in collection systems, tanks and components.
The nonprofit association that Pope leads has seen its membership grow from 90 members in 2007 to nearly 650 today. And cities and water utilities are starting to get interested in rain collection as well.
In San Francisco, Mayor Gavin Newsom has spearheaded a pilot program offering city residents 60-gallon rain barrels for $69.99, thanks to a subsidy provided by the San Francisco Public Utilities Commission and a price break from Cole Hardware.
Soquel Creek Water District offers a $25 rebate for rain barrels that hold 40-200 gallons and up to $750 for a 3,000-gallon container. Monterey Peninsula Water Management District offers a $25 rebate for each 100 gallons of capacity. The city of Palo Alto offers a $50 rebate on a rain barrel purchase. The Santa Clara Valley Water District is studying whether to add a barrel rebate program.
Adding a simple rain barrel to supply some water for landscaping is something anyone can do, Block says: "We can't all be Navy SEALs, but we can all be heroes in small ways."
What Americans need is a role model, he says.
"Michelle (Obama) needs to take the next step and install a cistern to water that White House garden."