Cross connection freqently asked questions

On this page are answers to common questions about cross connection devices and the City of Calgary Cross Connection Control Program.

If you have a cross connection letter, please visit Cross Connection Testing.

Cross connection questions and answers

What is a cross connection?

A cross connection is a temporary or permanent link between a potable (drinking) water system and any source containing non-potable water or other substances from which backflow may occur.

Examples include the piping between a public water system, or a citizen's water system and a heating or cooling system, fire system or irrigation system.

What is a cross connection control device?

A cross connection control device is a mechanical device that stops the backflow of water into public drinking water. The main testable types of cross connection control devices are

  • reduced-pressure principle assembly,
  • pressure vacuum breaker assembly,
  • double-check valve assembly, and;
  • registered Air Gaps.

Examples of secondary types of devices are the hose connection vacuum breakers, atmospheric vacuum breakers and residential dual check valves.

Note: A cross connection control device is NOT a backwater valve on a wastewater system.

Learn more about cross connection control devices in the brochures below:

What is backflow?

Backflow is the undesirable reversal of untreated water or other substances through an unprotected cross connection and into the piping of a public water system or a citizen's drinking water system.

There are two causes of backflow:

Backsiphonage: The reversal of normal flow in a system caused by a vacuum in the supply piping. This can also happen if there is an interruption of the water supply due to nearby fire-fighting, repairs or breaks in the water supply mains.

Backpressure: The reversal of normal flow in a system due to pressure higher than the supply pressure. This happens when there is an increase in downstream pressure caused by pumps, temperature increases in boilers, elevated tanks or other pressure-producing systems.

The regulations related to backflow and cross connections include the Water Utility Bylaw, the National Plumbing Code and the Alberta Amendments to the National Plumbing Code.

What are a homeowner's responsibilities?

Homeowners must ensure no cross-connections exist on their property that could contaminate their water supply. Cross connection locations include the following:

Outdoor cross connections:

  • Outside hosebibbs (i.e., garden hose attached to an outside tap or hose bib with the end of the hose connected to a pesticide sprayer; or left submerged in an ornamental pool, above-ground lawn watering);
  • In-ground lawn watering (irrigation) systems

Indoor cross connections

  • Toilets
  • Laundry sink connected with hose(s)
  • Handheld shower heads left immersed in water

Other cross connections

  • Boiler for in-slab or comfort heating
  • Fire protection system
  • Hot tub or spa
  • In-home water treatment (softener) system
  • High-pressure washer

You can also find more ways to protect drinking water in the Cross Connection Residential Brochure.

Why do cross connection control devices need to be tested?

These devices have internal seals, springs and moving parts that are subject to wear and fatigue; therefore, cross connection control devices have to be tested to ensure they function properly.

How do I test my cross connection control device?

If you are the owner of the property or an agent of the owner (such as a property manager), you are responsible for arranging a test.

For details on how to have your device tested, please visit Cross Connection Testing.

If you are a new owner of a property with a cross connection control device installed, or if you have recently changed your contact information, please call 311 to update your information.

Who are certified cross connection testers?

The names on our certified cross connection tester list have have an active registration with The City of Calgary. It is not an endorsement of the tester business practices or workmanship.

A certified tester is any individual who is registered with The City of Calgary Water Services as a Cross Connection Control Specialist within the mechanical industry (plumbers, irrigation, fire and sprinkler contractors, and mechanical contractors).

View a list of certified cross connection testers.

We do not accept reports from unregistered testers. A test report received from an unregistered tester will be returned and the device will be still considered untested.

What if I have received notice that I must install appropriate cross control assemblies?

Contract a City Qualified Trade Contractor who is a Cross Connection Control Tester and approved to obtain a plumbing permit to install the cross connection control devices.

A plumbing permit is required to install a testable cross connection control device. For additional permit information, please contact Building and Development.

What if I do not comply with testing or installation requests?

Failure to comply with the notification may result in a violation ticket, a water service cut-off and/or summary conviction as outlined in the Water Utility Bylaw​. 

To request an extension, please call 311 or submit an online service request.

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