The City of Cambridge Cross Connection Control Program is in place to ensure the safety of our drinking water through backflow prevention.

Our water use By-law No. 146-03 requires that all building owners, except some residential properties equip their buildings with backflow prevention devices. These devices need to be maintained and tested regularly by a backflow prevention device tester licensed by the City of Cambridge

Test reports must be submitted annually, and equipment surveys must be submitted every three years. 

At the design stage of a new building or addition a design level cross connection survey must be submitted with the building permit application.

Please see the Instructions for annual testing.

* NEW - The Cross Connection Control Program at the City of Cambridge is going paperless!

Starting this spring we will be sending out communications via email instead of paper mail.

If you are a property owner or primary contact person that is responsible for ensuring compliance to the City of Cambridge Cross Connection Control Program, we ask that you provide us with an email address to ensure you continue to receive important program information including testing due dates, reminders, updates and notices.

Please send an email from your chosen contact email to and include the following:

  • Your name and/or company name
  • The address of the property you are responsible for (see above)
What is backflow and how would this occur?

What is Backflow?

Backflow is the undesirable reversal of the flow of a possible source of contamination (water or mixture of water and other liquids, gases, or other substances) into the potable water system. 


Water is normally maintained at a significant pressure to enable water to flow from the tap, shower etc. If a water main bursts, pipes freeze or there is unexpectedly high demand on the water system, the pressure in the pipe may be reduced. During these types of events, the pressure may be reduced enough to reverse the intended flow of water and actually draw water out of nearby service connections. If these connections are affixed to chemical mixing facilities or any non-potable water supply, the possibility exists that dangerous backflow can occur resulting in contamination of our public water supply.
What is a Cross Connection?

A cross-connection is any physical or potential connection, whether permanent or not, between the public potable water system and a possible source of contamination such as non-potable water, industrial fluid, gas, or other substances.

Some examples of cross-connections are fire sprinkler and irrigation systems, or hard pipe connections to equipment that uses water, such as beverage machines and dialysis equipment.

If cross-connections are not properly protected, a backflow incident could contaminate a drinking water system. With modern drinking water systems, cross-connections are a necessity in a pressure piping system and cannot be eliminated. Therefore a means of protecting drinking water systems from contamination is essential.

What is a backflow prevention device?
This is a device that prevents water from flowing backwards into a water supply line resulting in a contaminated water supply. There are degrees of protection ranging from a vacuum breaker on a garden hose line to reduced pressure zone backflow preventers commonly used in an industrial setting where chemicals are connected to water lines. What is used and where it is installed depends on the application and the threat level.
What if I choose to not install a backflow device?
The by-law is clear that each building, except for some residential buildings require backflow prevention devices. Failure to equip the building and maintain these devices could result in having your water shut off, and/or a fine of up to $5,000.00.
Is there any fee or permit involved?

No. The annual testing and survey reports do not require a fee. However, if a new device needs to be installed it would require a building permit which would require a fee.

Please contact the Backflow Officer at (519) 621-0740 ext. 4514 for more information.