Flushing toilets with water may seem like something that always has been and always will be.  In reality, it’s one of the greatest misallocations of a valuable resource we’ve ever come up with.  Accessing freshwater is becoming a huge issue for not only third world countries, but for us here in the US of A… Good ol’ Benjamin Franklin stated a couple years back that “when the well is dry, we know the worth of water.”

Toilets are major culprits in water consumption in both residences and commercial buildings.  That’s why what the CK Choi building in Vancouver BC has done is absolutely incredible…. The 30,000 sq ft structure is 100% sewer-free!

How in the world might they accomplish something like this?  Well, they utilize a number of strategies including composting toilets, waterless urinals, graywater recycling and rainwater capture.  The toilet system is the most innovative.  The graph below shows how the system works… basically there’s a composter in the basement with a fan system that doesn’t allow air to escape.  THe building maintenance crew adds a bag of wood chips or bark mulch to each toilet every day, speeding up the composting process.  Every six months, the compost is removed from the system and becomes fertilizer.

The CK Choi building uses an astonishing 132 gallons of water a day!  A similar sized structure with normal water habits would go through 1850 gallons each day…. so what does this mean?  Basically that modern buildings can be self reliant on small and large scales in regards to the sewage system.  A huge amount of water ($$$) is saved each year, and pressure is taken off of water treatment facilities down stream.  The fertilizers, captured rainwater, and recycled gray water can be used to take care of all landscaping needs.

Wow… someone was thinking, eh?

good stuff,


About Joshua Foss

Joshua is a leading voice for transformational change. He is the editor of Metro Hippie, co-founder and director of development of the Ecala Group, and adjunct faculty at the Minneapolis College of Art and Design. He is also an ambassador for the Living Building Challenge and is a frequent speaker at national conferences, trade shows and summits.