Although the energy crisis has long held our attention in the green building world, the global water crisis urgently needs our attention. That’s because we can do a lot to reduce the consumption of water, and in particular, potable water, in the way we design our buildings and neighborhoods. To celebrate World Water Day, and its 2011 focus on urban water systems, our friends at the Cascadia Green Building Council (CGBC) have released “Toward Net Zero Water: Best Management Practices for Decentralized Sourcing and Treatment.”
The authors, Katie Spataro and Joel Sisolak, Cascadia’s Research Director and Advocacy and Outreach Director, respectively, have produced what I predict will be a significant capacity building tool for communities hoping to achieve net zero water at the building and neighborhood scale. The report contains an overview of best practices and technologies for decentralized and distributed water systems, with special focus placed on rainwater harvesting, greywater reclamation and reuse, and on-site wastewater treatment for reuse – the systems that face the highest hurdles when it comes to permitting them. (Presumably it is for this reason the manual does not address on-site stormwater management systems and fixture efficiencies, both of which do contribute to net zero water schemes, but also enjoy greater regulatory acceptance in the past few years. There are also plenty of resources out there on these topics, including one O'Brien & Company helped develop: “The Low Impact Development (LID) Guidance Manual for Kitsap County".)
Each BMP chapter describes major system components, how the systems work, and background on appropriate scale and efficiency. Design considerations are provided for system sizing, location, and integration with other building systems. And, because case studies can be very compelling, there are several demonstrating the best practices covered. The manual is more of a planning tool then a design tool; for each system, resources are provided to find more in-depth technical details.
Katie and Joel have done their homework and made it easy for us. Though there is a tremendous amount of information on these systems out there, it isn’t easy to access in a methodical, efficient manner. They’ve sifted through it all, gleaned the credible data, and organized it in a way that is useful. No fear, this is not a “cheerleading” document, but you also don’t have to be an engineer to “get it.”
The Living Building Challenge’s net zero water imperative requires “closed-loop” water systems, and that is the focus of the manual. Mark Buehrer, of 2020 Engineering, and a peer reviewer for the study has long held that closed-loop water designs are “critical for net zero water buildings.” I concur. Similar to the low impact development approach to stormwater, decentralized on-site closed-water systems can mimic nature better. Because they are more site-appropriate, they will be diverse, but the overall approach of these small-scale systems remain the same: begin with super-efficient measures to reduce overall water demand, and then treat the water needed for potable and non-potable uses.
When faced with the facts that many cities around the country are anticipating water shortages; that the cost of replacing our steadily degrading water and wastewater infrastructure is huge; and that the money (and political will) to invest in centralized infrastructure is dwindling, it only makes sense to stop using potable water for uses that don’t require it, and to find more agile and effective ways to supply and treat our water.
Building Capacity Blog is edited by Kathleen O’Brien, a Cascadia Fellow, and President of O’Brien & Company, a green building consultancy, founded nearly 20 years ago, and located in Seattle, Washington, providing services in green project consulting, sustainability policies, plans, and programs, and education. Sisolak and Spataro are among the line-up of presenters at this year’s Living Future (April 27-29 in Vancouver, BC). Their session, “Getting to Net Zero,” digs into the elements of the Living Building Challenge water petal and regulatory challenges impeding the progress of net-zero water projects. Cover image courtesy of Cascadia Green Building Council.
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Envisioning a Net-Zero Water Future
Interview with Schacht Aslani Architects’ Walter Schacht
Interview with Kitsap Home Builders Foundation’s Art Castle