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| Ultimate Home Design News | ||||
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March 5, 2010
Rainwater To Meet All Of San Juan Island Home’s Water Needs Glen and Deb Bruels have gotten great news for water-starved San Juan Island: the rainwater they capture in their underground cistern will meet 100 percent of the drinking, bathing, laundry and flushing needs for their new sustainable house on the island’s northwest coast. Rain is scarce on the island, which is 65 miles north of Seattle, because it lies in the rain shadow of the Olympic Mountains. For six months out of the year water in the Bruels’ neighborhood comes from a desalination plant that makes fresh water out of the surrounding salt water. This process takes a lot of power: to convert a day’s worth of water requires as much energy as running three refrigerators for a day. Well water is available the remainder of the year. The Bruels turned to Rob Stevens, Senior Project Engineer at Core Design Inc. in Bellevue, Wash., to model a system to harvest and store water for their “Natural Balance House” (www.naturalbalancehouse.com). The result is a 19,500-gallon cistern dug from the bedrock under the house and accessible through a floor hatch in the master bedroom closet. “In a pinch, it could double as a ‘panic room,’” jokes Bruels. To determine the size of the cistern needed, Stevens first determined that the Bruels require 62.5 gallons of water per person per day. That’s less than the U.S. average, thanks to the water-saving fixtures and appliances they’ve chosen for their new home. They will also need enough water to irrigate a small garden area outside the home with an efficient drip irrigation system. The home’s roof is expected to collect 47,000 gallons over the course of a year. The home features both a metal roof and a 3,000-square-foot “green roof,” planted with native grasses and sedums. Rainwater falling on both the metal and vegetated roofs will be collected and filtered and sent to the underground cistern. In addition to the filtration system, the water will pass through an ultraviolet-light disinfecting chamber to remove any trace bacteria. The resulting water will be so pure that no chemicals will need to be added to make it drinkable. “My analysis, using the most conservative assumptions, shows that the cistern will still have 4,000 gallons of water left at its lowest point,” says Stevens. “The Bruels should feel comfortable taking an occasional long shower or having visitors over for dinner.” Designed by Michael McNamara and built by Ravenhill Construction of Friday Harbor, WA, the Natural Balance House is pursuing five major green certifications: · First LEED® certified home in the San Juan Islands (targeting Platinum) · First Emerald Level National Green Building Standard™ Home in Washington State · Five-Star Built Green® certification · Certified ENERGY STAR® Home · U.S. Department of Energy Builders Challenge Home **Photos available on request. |
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