The City of Ottawa’s Backflow Prevention Program protects drinking water quality by ensuring the appropriate installation and inspection of devices that prevent contaminated water from flowing back into the City’s water distribution system, as required under Schedule H of City of Ottawa Water By-Law 2013-360, as amended. The program supports compliance with the highest industry drinking water protection standards to ensure public safety and the long-term safety of our shared water resource.
Backflow prevention programs are currently in place in numerous Ontario municipalities, including Toronto, Hamilton, London, Markham, Halton Region and Waterloo.
The Backflow Prevention Program Report was approved by Council on June 28, 2017.
Who is affected?
While the Backflow Prevention Program will not apply to the majority of City drinking water customers, it will impact approximately 15,000 industrial, commercial, institutional and multi-residential properties classified as severe or moderate risk for backflow incidents.
Properties that pose a severe risk include manufacturing and automotive facilities, hospitals and dental clinics. Properties that pose a moderate risk include apartments, hotels, motels and schools. The program will address moderate risks from multi-residential buildings that are over three stories or have a footprint over 600 m2 (or 6,458 ft2).
Standards and regulations
The standards for backflow prevention are established in the Canadian Standards Association (CSA) Manual for the Selection and Installation of Backflow Preventers/Maintenance and Field Testing of Backflow Preventers (CSA B64.10) and the Ontario Building Code.
The program will require premise isolation (the separation of a property's private water system from the City's drinking water supply) for all severe and moderate service connections through the installation of premise backflow devices in accordance with CSA standards.
CSA standards define severe, moderate and low hazard to drinking water systems:
- Severe hazard: Any connection or potential connection that involves water that has additives or substances that, under any concentration, can create a danger to health.
- Moderate hazard: Has a low probability of becoming a “severe hazard.” The water’s aesthetic qualities have been further reduced, and under certain conditions, may create a danger to health.
- Low hazard: Any connection or potential connection that involves a substance, which has reduced the water’s aesthetic quality, this could involve water that has been heated or cooled. Generally, these hazards are a nuisance only, and upon consumption pose no danger to health.