Harvesting rainwater for soft water use – not easy!

The following article, “Hard Water – When it comes to standards and guidelines, harvesting rainwater isn’t as easy as it looks” by Kevin Wong appeared in the May/June 2011 issue of WaterCanada

In the last few years, as the provinces have had to wrestle with water conservation programs, policies, and myriad associated aspects, one of many topics has posed a significant challenge: how to handle rainwater harvesting and use.

Video and images used in this blog are not part of the article.

Youtube video,”Solutions for Development: Rainwater Harvesting”, uploaded on Mar 6, 2007 ~ Dr. Kent Butler explains the benefits of rainwater harvesting ~

underground cisternThere are a number of hurdles that provincial policy makers and their municipal counterparts have to handle. First, in Canada, there is just no easy template to handle greywater and, by association, rainwater. 
CDN PLUMB ASSNHere’s why. The Canadian Standards Association (CSA) standard for the design, installation, and maintenance of non-potable water systems (as it was referenced in Canada’s National Plumbing Code) was not adequate for adoption by the provinces. It did not offer proper guidance on intended water quality, backflow, maintenance, or testing. Development of guidelines for rainwater, water treatment, and other aspects that are critically needed by the provinces and the municipalities is ongoing.
Additionally, rainwater and storm water definitions are synonymous in Canada. Each carries some connotations that make it difficult to segregate the two definitions in policy. The difficulty results in an inability to offer simplified water treatment options for PLUMBING CODErainwater harvesting. There is a glimmer of hope, however. Provinces such as Ontario, British Columbia, and Alberta have taken the leap and attempted to make these landmark changes to policy. Already there are draft changes posted for the next edition of the Ontario Plumbing Code.


In the future, it’s hoped that the result would make it easier, policy-wise, to collect, disinfect (treat), and distribute rainwater to the home for a number of applications (some of which may not be available for treated greywater), such as showering or laundry. While the theory would be to use rainwater and appropriately treat for potable drinking water uses, the framework is not yet available in Canada.
AMERICAN PLUMB ENGINEERS Finally, the storage aspect of water storage is missing. In its rainwater harvesting guide, the American Society of Plumbing Engineers suggests that stored water does not need to be disinfected. Before disinfection for rainwater storage can be evaluated, containers would need to meet cistern or storage vessel standards like CSA B126. That standard is in the works.
wet_holding_tank_trailerThe water treatment technology to properly assess, manage, and set up water reuse systems exists. It doesn’t matter whether it’s a rainwater or greywater
grey water re-use
reuse system—what’s missing are the essential and proper standards and guidelines to bring the policy makers to a comfortable level as they mandate these systems into general policy.

cisternThere are models out there which we can turn to for best practices in the absence of these documents. We have a long way to go before we solve this challenge, but we’re working on it. 
WONGKevin Wong is the executive
director of the Canadian Water
Quality Association

Related link http://www.greenvillecounty.org/soil_and_water/pdf/rain_harvesting.pdf


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