Ask Ashley
Greywater Gains Ground
February 19, 2008
Q:
Dear Ashley,
I’ve come across several do-it-yourself greywater systems in magazines and I’m wondering if they are permitted for use in Calgary. Is there a preferred system for Calgary?
With regards,
Paul
A:
As the pressure on finite supplies of water increases people are forced to look for creative ways to stretch the water available to them. Calgarians, not unlike most North Americans, receive all of their water treated. This means that water for washing the car, watering the lawn and garden and flushing the toilet is all the same – water treated to the highest standards such that it is deemed potable (drinkable). Treating water to this level for all purposes streamlines the process but this comes at a great financial and environmental cost, as treatment is highly energy intensive. Water reuse has been shown to not only take pressure off of the treatment infrastructure and local watershed but also supply abundant and cost effective water to areas where treatment is unnecessary.
Water reuse can be categorized into three main areas: storm water reuse, potable water reuse, and wastewater reuse. Residents may, assuming the regulations are in place, take advantage of the first two aforementioned types. Rain barrels make use of storm water and are becoming increasingly popular in Calgary for lawn and garden irrigation. Less popular but an area that promises big returns is potable water reuse, also referred to as greywater. This is the wastewater from domestic uses such as bathroom sinks, showers and clothes washers. Although not widespread in Canada, greywater is widely used in the drought stricken southern U.S. and in many other parts of the world.
Greywater systems basically involve reworking the plumbing so that the water is directed to the garden, the back of the toilet or to a holding tank where it can be fed to various places in a controlled manner. The water itself is as good as what’s put into it. Caution should be exercised when selecting cleaners and personal care products, choosing products that are low in sodium, nitrogen and phosphorus, while making sure that they are readily biodegradable. Systems range from the simple - where water is directly fed to where it’s needed - to the complex, typically involving some level of on-site treatment. The desirable system for a particular area is usually detailed by the local government but, in Canada, a lack of regulation and the large number of government agencies involved have restricted the number of greywater projects. Luckily, though, this appears to be changing.
A growing number of Leadership in Energy and Environmental Design (LEED) projects have successfully incorporated water reuse technologies to the benefit of both the user and the environment. These include several high profile projects in Calgary: the Vento residential building in the Bridges, using storm water for irrigation and toilet flushing, and the new City of Calgary Water Centre, which will reuse water from the meter test shop for toilet flushing and irrigation. Projects such as these not only help to increase public understanding of water reuse but it also forces government to deal with the issue of enacting legislation such that water reuse is seen as an acceptable practice.
In 2006 a motion put forth by Alderman Hawkesworth was passed which discussed options for promoting water conservation by reducing barriers for the safe use of non-potable water and the reuse of greywater. The report was presented to council in February 2007 and from what I hear the special committee will be going back to council this month to discuss the issue further. Building on this, a draft has just been completed at the federal level, establishing the “Canadian Guidelines for Household Reclaimed Water: for use in Toilet and Urinal Flushing”. While neither discussion is finalized, it would seem that the tide is turning and we may begin to see a growing number of projects incorporating both storm water and greywater in the near future.
Reusing water allows people to substitute high quality drinking water with water suitably treated for its intended use, while reducing river withdrawals, minimizing sediment loading from storm water runoff, and limiting the need for further costly, energy intensive water treatment. This is especially important in summer when water supply is the lowest and water use is the highest - at times tripling to keep lawns well watered and green. Given Calgary’s growth and its dependency on a water supply that is, at times, stretched to its limits it would be wise for governments to remove the barriers that limit water reuse, thereby helping to safeguard our precious water supply well into the future.
For those that are keen to get the gritty details I’d suggest checking out Create an Oasis with Greywater by greywater guru Art Ludwig.
Cheers,
Ashley
Ashley Lubyk, BSc. in Environmental Science, formerly a Calgary Materials Exchange Program Assistant at Clean Calgary Association. Please send your question concerning Water, Waste, or Recycling to Ashley.