Building Blog #3 What is grey water... And why should I care? / by Sustainable

Greywater or sullage is all wastewater generated in households or office buildings from bathroom sinks, showers, tubs, dishwashers and washing machines without fecal contamination (which is referred to as domestic wastewater or black water).  

While greywater may look “dirty,” treated greywater is a safe and even beneficial source of non-potable water for various domestic and commercial uses.  As greywater contains fewer pathogens than domestic wastewater, it is generally safe to handle and easy to treat and reuse onsite for toilet flushing, landscape or crop irrigation, and another non-potable uses. Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products. Reusing grey water has been a proven method towards operating a building sustainably and cost effectively.

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Simple everyday tasks of toilet flushing and bathing represents about 65% of daily water usage in a Canadian household. Using reclaimed greywater from showers and baths eliminates the use of potable water for toilet flushing, resulting in significant annual water and wastewater cost savings for the home and the city.

Aside from the obvious benefits of saving water (and money on your water bill), if greywater is released into rivers, lakes, or estuaries, its nutrients become pollutants. reusing your greywater keeps it out of the sewer or septic system, thereby reducing the chance that it will pollute local water bodies. But introducing it to plants it acts as a valuable fertilizer. Reusing greywater for irrigation reconnects urban residents and our backyard gardens to the natural water cycle.

The application of greywater reuse in urban water systems provides substantial benefits for both the fresh water supply system by reducing the demand for fresh clean water as well as the wastewater system by reducing the amount of wastewater required to be conveyed and treated, thus reducing processing carbon footprint.

Canadians have access to some of the highest quality water in the world. Despite our abundant supply of fresh water, it remains a limited resource as much of it is not readily accessible. Our future water supplies are less certain than what we enjoy today, and some countries and certain regions in Canada have already begun to experience residential water shortages. Greywater can provide an alternative source of water for domestic usage to ensure that the future usage of water remains sustainable.

Residential greywater systems are a low-cost, high-impact sustainable technology. A second set of clearly labeled piles are roughed-in by the plumber, connecting certain drains down to the mechanical room, with additional lines leading to the toilets and irrigation cisterns. The greywater pump, fillets, and tank can be installed at a later date if required, but the time of renovation of construction it is a simple installation. Research and calculations show that to a family of four, you can start saving money and reduce you water usage on day one.

To learn more about grey water systems and get one installed on your project please reach out to our friends at Greyter Water Systems or simply give SUSTAINABLE.TO a call.