Backflow prevention

Learn more about the backflow prevention program for drinking water, including survey forms, accredited testing companies, permit applications and applicable fees.

On this page

  1. What is backflow?
  2. Install backflow prevention devices
  3. Prevent backflow in your home

What is backflow?

Our distribution system is designed to supply drinking water into homes and businesses. Backflow occurs if drinking water flows in the opposite direction: from homes and businesses back into our distribution system. This can result in pollutants and contaminants entering our drinking water. 

Install backflow prevention devices

Our prevention program works with industrial, commercial, institutional and multi-residential property owners to prevent backflow into the drinking water system.

Property owners are responsible for installing, maintaining and testing backflow prevention devices, which require a permit to install.

Installation process

  1. Hire an approved testing company — email for a list.
  2. Have the company complete and submit the cross connection survey form (PDF).
  3. Apply for a permit to install a backflow device (PDF).
  4. Once the device has been installed, submit a test report (PDF).


  • Backflow test report fee: $27.25 (Backflow test reports must be submitted within 45 days of receiving the reminder letter, or late fees will apply.)
  • Late Backflow test report fee: $54.75
  • Permit fees start at $83.00 and can range upwards depending on the number of devices installed and the cross connection survey review. Submit your permit application form or contact the backflow prevention team for an estimate at 519-886-2310 or

Removal process 

  1. Complete an authorization to remove backflow device form (PDF). 

Prevent backflow in your home

Single-unit home owners do not have to take part in the prevention program above, but can still help to limit the potential for backflow through simple 'dos and don'ts'


  • keep hose ends clear of possible contaminants
  • install vacuum breakers on threaded faucets and hose connections around your home. These devices are inexpensive and are available at hardware stores
  • install an approved backflow prevention device on above ground lawn irrigation systems


  • submerge hoses in buckets, pools, tubs, sinks or ponds
  • use a hose to unplug a blocked toilet
  • use spray attachments without a backflow prevention device
  • connect waste pipes from water softeners to the sewer or submerged drain pipes

For more information on backflow prevention see our Backflow Prevention Bylaw