As per the City of St. Catharines' Water By-law and the Ontario Building Code, all commercial, institutional, industrial and large, multi-level residential property owners must install backflow prevention to avoid water flow reversal and cross-contamination through water lines. New construction projects in these types of buildings are required to have backflow prevention upon build.
Our Backflow Prevention Program ensures facilities have proper backflow prevention techniques installed.
Defining backflow
Backflow is the reversal of the normal direction of water travelling through a water line. Within water lines, cross-connections exist, which are connections between the drinking water supply and a non-potable source of water.
When backflow occurs, contaminants can be introduced into the drinking water supply through these cross-connections and distributed through the system to users.
Potential causes
Backflow can occur in two different ways: back siphonage and backpressure.
Back siphonage
Back siphonage occurs when there is a significant drop in pressure in the main distribution pipes, which can pull water back into the system from any nearby connections. The drop in pressure is caused by lots of water being removed from the system, such as during firefighting or a watermain break. An example of this is shown when a garden hose is left in a pool. When back siphonage occurs, the pool water can be pulled back through the hose into the watermain and delivered to the tap of a nearby residence or business.
Backpressure
Backpressure is caused when the pressure on the water customer's side of the connection is greater than the pressure in the City's distribution system. This pushes water back into the system.
Backflow Prevention
There are many types of backflow prevention devices available depending on the application and degree of contamination risk. Speak to a qualified plumber or water servicing company for assistance in selecting and installing the proper prevention devices for your needs.
View a list of companies providing backflow prevention services.
If you are deemed to be a backflow risk
If you are an owner of a property deemed to be a backflow risk, our staff will contact you to have a qualified backflow prevention specialist complete our Cross-Connection Survey at the owner's cost. The survey will identify any existing backflow risks to the water distribution system and recommend the appropriate improvement methods. This could include appropriate backflow prevention devices for premise and source isolation.
You can submit completed surveys by email to backflow@stcatharines.ca. We require the survey to be completed every five years to ensure proper backflow prevention is in place.
Premise isolation
Premise isolation is the installation of backflow prevention at or near the water meter, prior to any other connection to the water service for the facility. This protects the City's water distribution from possible contamination.
Source isolation
Source isolation is the installation of backflow prevention within a facility to isolate a cross-connection from the internal water distribution system. This protects people within the facility.
Installing backflow prevention devices
When acting on the results and recommendations of your completed survey, you must install new backflow devices using a qualified plumber. Plumbing permits are required and available at City Hall. You must notify us when installations are complete. Our plumbing inspector will inspect the site to ensure completed work.
Regular device testing
Certain backflow devices must be tested upon installation and each year after to ensure they are properly functioning. The testing must be completed by an Ontario Water Works Association (OWWA) certified tester, who must complete either the Double Check Valve or Pressure Vacuum Breaker Backflow Prevention Device Test Report or the Reduced Pressure Principle Assembly Backflow Prevention Device Test Report. Please submit the completed report to our staff when ready.
Device tags
Your qualified plumber must attach identification device tags to each device, signed and dated by the tester. You can pick up these tags from our Plumbing and Building Service counter at City Hall.