What makes Desert Rain unique is the standard to which it is being built. The Living Building Challenge is both a philosophy and set of principles that guide us toward true sustainability. Living Buildings are designed and constructed to work as efficiently as possible on the resources available in a given space. As stated by the International Living Building Institute, “The underlying principle of the Living Building Challenge (LBC) is that the built environment should regard nature as the ultimate measuring stick for performance.”
LBC puts forth seven performance areas—called Petals:
Petals are subdivided into 20 imperatives that focus on a specific sphere of influence. We’ll discuss all of these over time, and you can explore them at www.ilbi.org/lbc, but given that Desert Rain’s cistern is taking shape I’d thought we’d touch on one imperative under the Water Petal: net zero water.
Petal: Water • Imperative 05: Net Zero Water
Net zero water means that 100% of Desert Rain’s water use must be supplied by precipitation at the home site. Bend’s high desert climate averages just over 11 inches of annual precipitation (average based on weather data collected from 1981 to 2010 for the National Oceanic and Atmospheric Administration). That’s just enough for small family home. That precipitation will be gathered from the various roof tops on the property—the home itself, as well as the accessory dwelling unit and the two garages—and piped down for storage in the 35,000 gallon cistern.
To meet LBC standards, Tom and Barbara are allowed one initial fill-up of the cistern from city water. After that, to meet LBC, they must be able to live within their water means. That is, they can only use what the skies give. If an average family of four needs about 73,000 gallons of water a year, and the roofs at Desert Rain can collect roughly 30,000 to 40,000 gallons, efficiency with water is will be key. Every water fixture in the home will be highly efficient, and Tom and Barbara themselves are already living within a water budget that will be similar to what they’ll need to live under once they move into Desert Rain. Landscaping, of course, is also designed to fit within the area’s water means.
The Desert Rain cistern will be located under the home’s main garage. The hole for this concrete structure is so massive that workers need a ladder to get in and out of it. The digging was a long, arduous process—weeks of hammering away at rock with a hydraulic excavator. Last week the footings were poured and set. This week they’re placing the forms for the walls and pouring that concrete as well.
While cisterns are more common in outlying areas dependent on wells, and in areas where water is scarcer, you rarely find them in the middle of a mid-size town. Which is perhaps why I’m so fascinated by this aspect of the project. Imagine—not using water from your municipality. Using only what the environment provides.
This basic concept could have huge ramifications if it took hold. Think of the lawns we water, the cars we wash, the long showers we take—all the things that take up so much more that what nature provides in many cases and places. It certainly provides food for thought.
The intent of the Water Petal is to realign how people use water and redefine ‘waste’ in the built environment, so that water is respected as a precious resource. Scarcity of potable water is quickly becoming a serious issue as many countries around the world face severe shortages and compromised water quality. Even regions that have avoided the majority of these problems to date due to a historical presence of abundant fresh water are at risk: the impacts of climate change, highly unsustainable water use patterns, and the continued drawdown of major aquifers portent significant problems ahead.
– From the Living Building Challenge standards