Backflow Prevention

Since 2008, all commercial, industrial, institutional and large multi-residential (five units or more) buildings must have approved backflow prevention in place to protect our drinking water from contamination.

Backflow prevention schedule

1. Cross connection assessment done by a Certified Contractor
   (Copies must go to Backflow Prevention Officer and property owner. Email the Backflow Prevention Officer.)
2. Apply for a Building Permit and pay (this step usually done by contractor).
3. Contractor installs required upgrades, including testable backflow prevention devices
4. Certified Contractor tests backflow prevention devices
   (Test report copies must go to Backflow Prevention Officer and property owner. Email the Backflow Prevention Officer.)
5. Contact City Backflow Prevention Officer (807-626-3828) for an inspection to approve installations
6. Testable devices must be tested every year by a Certified Contractor
   ($50 renewal fee applied to water bill as per Waterworks By-law 029-2018)
7. Have a new cross connection assessment done by a Certified Contractor every five years as well as annual testing

PLEASE NOTE YOUR RESPONSIBILITIES: Please make a note of your annual testing date. Every year, you must have your devices tested by a Certified Contractor. Every five years, you must have your cross connections assessed.

We email reminders to you. We require your up-to-date email address and phone number for this mandated program. Please Contact our Building Division Clerk to provide this information.

If you do not provide updated information, you will not be notified of your responsibilities. Not supplying contact information may result in non-compliance with the Backflow Prevention Program, which can lead to fines up to $100,000 and/or termination of your water service.

What is Backflow?

Normally, drinkable water flows from the City's distribution system into the plumbing in a building. Backflow is the reversal of that water flow direction. Water that flows into the City's distribution system from a private water system is moving in the wrong direction, and potentially can allow contaminated water into the City system. Water can backflow from private water system components such as boilers, sprinkler systems or chemical dispensers. Causes of backflow include water main breaks, fire hydrant flushing and firefighting.

The risk of backflow can be eliminated by installing the appropriate backflow prevention devices.

The Backflow and Cross-Connection Prevention Program is part of the City of Thunder Bay's Waterworks By-Law 068-2018, developed in accordance with the requirements of the Provincial Safe Drinking Water Act. This Act requires all Municipal Drinking Water Systems to address risks to the safety of the distribution system, including the risk of backflow from contaminated water.

Non-compliance with the Backflow Prevention Program can lead to fines up to $100,000 and/or termination of your water service.

If you require a PDF in an accessible format, email our Municipal Accessibility Specialist.