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People in developed countries use a substantial amount of water. According to the Environmental Protection Agency, the average American family of four uses over 1,500 litres of water every day. Most of that usage can be traced back to the bathroom, where water-intensive toilets, showers, and sinks are located.
While the water flushed down the toilet is known as blackwater, the wastewater drained from sinks, showers, bathtubs, and washing machines is known as greywater. Though greywater may contain traces of food, detergents, grease, and other potentially harmful pollutants or pathogens, it can be filtered, treated, and reused for other applications. Water may not seem like a finite resource for those in developed countries, but the UNESCO International Hydrological Programme has encouraged the recycling of greywater wherever possible to combat the global water crisis.
Numerous sustainable building projects around the world are incorporating greywater recycling systems into their designs for purposes like on-site landscaping irrigation. That's the vision outlined in the self-sustaining Hyperions project in India. Greywater can also be used for flushing toilets in jurisdictions that have adopted the International Plumbing Code. A residence using such a system could save up to 30% on their water usage.
Closer to home, greywater systems have been installed in numerous projects around the Greater Toronto Area for various purposes. Greyter, a water systems company headquartered in Mississauga, lists numerous installations here, with examples including the Aviva office building in Markham, the MEC store in North York which uses rainwater collected onsite to reduce city water consumption in its toilets, and Chaz Condominiums in the Bloor-Yorkville area where rainwater is collected in a cistern before being used to irrigate the lawns and plantings at the site.
Similarly at Almadev's Emerald City near Don Mills subway station, has an extensive system in place. Greyter's summary of the Emerald City system reads "The two Greyter systems collect storm water so that it can be used for irrigating the complex’s lawns and gardens. Many new residential condominiums utilize Greyter’s solutions in order to collect, treat, and use accumulated rain and storm water on site in order to reduce water costs, as well as to prevent excess run-off of storm water into the sewers. This assists in reducing the demand on infrastructure, diverting runoff, and reducing surface flooding which can often cause combined sewers to overflow into local waterways."
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From 2015 to 2017, UrbanToronto and its sister publication, SkyriseCities, ran an occasional series of articles under the heading Explainer. Each one took a concept from Urban Planning, Architecture, Construction, or other topics that often wind up in our publications, and presented an in depth look at it. It's time to revisit (and update where necessary) those articles for readers who are unfamiliar with them. While you may already know what some of these terms mean, others may be new to you. We are publishing or updating and republishing Explainer on a weekly basis. This article is an update of one that was originally published in 2016.
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