Backflow preventer

Your drawings must clearly show what is existing and the changes you’re proposing. Drawings must be to scale, and should use metric measurements. We may request additional information when your application is reviewed.

For a backflow preventer you’ll need to submit:

The site plan must include the following:

  • Address
  • Road location
  • Location of proposed backflow device installation

Detailed drawings sealed, signed and dated by a professional engineer showing:

  • Installation methods of the backflow prevention device
  • Expansion tank details complete with sizing calculations, a certified thermal expansion relief valve with reference to the applicable CSA Standard, or other method deemed acceptable by the authority having jurisdiction


  • Backflow prevention device valve specification with reference to the applicable CSA B64 Standard

If the backflow prevention device(s) is to be installed in a water system that serves a fire protection system (sprinkler, standpipe), additional details will be required.

Learn more about backflow prevention serving fire protection systems.

Contact us

If you need more information, call 311 (905-615-4311) or contact us online.