The City of Vancouver requires that backflow prevention assemblies be installed to protect drinking water from contamination by the backflow from water used for other purposes. Backflow prevention assemblies must be tested after installation, and tested annually by a certified tester, in accordance with the Vancouver Water Works Bylaw 4848. 

If your water system has cross connections, you are at risk of backflow contamination. Older buildings are susceptible to these as they have fire suppression systems. These old systems have black iron piping systems that could potentially contaminate potable water systems with lead. In these cases, backflow devices are crucial to ensure that the potable water is not contaminated.

When backflow accidents happen, your water can be reversed. Even if it is only for a short period of time, the consequences can be extremely serious. Non-potable water can contaminate the fresh water supply and result in waterborne diseases that cause health risks. Contaminants that could be introduced include Encolpia, Salmonella, Giardia, and other toxic chemicals such as pesticides, metals, and volatile organic compounds.