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Preventing backflow in your business

The City requires businesses to prevent backflow and adhere to the City's Backflow Prevention Program. The Program is regulated by the City’s Water By-law and is based on the CSA/CAN B64.10/B64.10.1 Standard: Selection and installation of backflow preventers/Maintenance and field testing of backflow preventers.

To learn more about preventing backflow and selecting a backflow prevention device, please continue reading.

How can I prevent backflow in my business?

Backflow can be prevented in your business using two methods:

  1. Leave an air gap of at least one-inch between the end of a hose/pipe and the surface of a container of liquid.
  2. Install a mechanical device that prevents backflow, when an air gap is not practical. This mechanical device works by shutting the hose/pipe when water begins to flow backward.

Air gap illustration Typical cross connection

What type of device should I have installed to prevent backflow?

Contact 204-986-4118 or to find out if you need a backflow prevention device and the type of device needed.

The degree of hazard determines the type of device required. The device can either be installed just after the water meter, or just before the potential source of contamination.

There are three degrees of hazard:

Degree of hazard Description Examples of properties Examples of potential sources of contamination Requirement/ recommendation
Severe/high Any cross-connection involving substances that can create a danger to health at any concentration hospitals, laboratories, morgues autoclave, chemical feed tank, heating system (chemicals added) a reduced-pressure assembly (required)
Moderate Any cross-connection involving substances that, under certain conditions, can create a danger to health office buildings, shopping malls, commercial properties irrigation systems (no chemicals added), steam generators, heating systems (no chemicals added) a double check valve assembly (required)
Minor/low Any cross-connection involving water that cannot create a danger to health but may create a nuisance duplex, residential property beverage dispensing equipment (no carbonator), water softener a dual check valve (recommended)

See CAS/CAN B64.10.1 Standard: Selection and installation of backflow preventers/Maintenance and field testing of backflow preventers for additional examples.

Is a plumbing permit required when installing a backflow prevention device?

Yes, a plumbing permit must be acquired before installing or replacing a backflow prevention device. Permits can be obtained from Planning, Property and Development Department.

Whose responsibility is it to test backflow prevention devices and what are the testing requirements?

The property owner and/or occupant are responsible for maintaining and testing backflow prevention devices.

Testing must be performed:

  • by a licensed backflow tester
  • using properly calibrated test equipment
  • at the time the backflow prevention device is installed, repaired, replaced or relocated, and annually thereafter
Why do backflow prevention devices have to be tested annually?

Mechanical backflow prevention devices have internal seals, springs and moving parts that can become dirty and wear out. They must be tested annually with properly calibrated equipment to ensure they are working properly.

How do I submit completed test reports?

Use this fillable PDF form to submit a test report online.

This can be filled out online and can be printed or emailed directly to us. To submit the form, fill out the required fields and click the "Email this form" button at the bottom of the form.

Once sent, a copy of the report will be in your sent items folder.

*Please open and fill this form with the Adobe Reader plugin. You may experience some difficulty viewing the content of this PDF if you are using the built-in PDF viewer in your browser. Visit Adobe Support for more information and assistance.

Completed test reports must be sent to the Backflow Prevention Office within 14 days by:

  • by mail to 2230 Main Street, Winnipeg, MB, R2V 4T8,
  • by fax at 204-986-4809, or
  • by email at
  • online, using the fillable PDF test report

The test report must be completed by a licensed backflow tester.

You are required to keep a copy of the two most recent test reports on-site or have them readily available.

Last updated: August 7, 2018