While searching around the 100K house website this morning, I came across the concept of Net Zero Water. Now you all know what Net Zero Energy is - building with zero net energy consumption, zero carbon emissions annually and being 'off the grid.' Well, Net Zero Water is a similar concept.In order to be considered 'water independent' a building needs to capture all precipitation, manage its storm water runoff and re-use all household wastewater.
Wastewater can be considered either greywater or blackwater (water that has come into contact with human waste or other organic matter) and different types of water require different types of treatment. Rainwater can be captured, stored, and treated with a relatively small amount of energy. Rainwater is fairly clean - it just requires ultra-violet sterilization to be used for drinking purposes. Greywater can be naturally filtered in a constructed wetlands system, or living machine.
Now you have to admit, the concept of Net Zero Water is a tough call, even for those of us who live in areas that get a lot of rain. For people living in Arid regions of the U.S. its basically impossible. But if you're building and you want to build green, you can opt for a greywater system. This one is a nice little streamlined stand alone system designed to serve a typical household of 4 - 6 people. It captures water from your bath and shower, cleans it and channels it to your toilets. After all, why flush clean drinking water!
There are many new water use concepts that we need to develop. Water is a reusable resource but not a renewable resource. The amount we have in all of its forms is all there is. It is our most precious resource after oxygen and we need new paradyms for thinking about and using it.
H. Court Young
Author, publisher, speaker and geologist
Author of Understanding Water Rights and Conflicts