Cross Connection Devices

For the City of Calgary, a cross connection is any temporary, permanent or potential water connection between a drinking water system and any source containing non-drinking water or any other potential contamination substance from which backflow may occur. Improper plumbing or cross connections can contaminate the public drinking water supply, making testing an essential check on residential and commercial clients.

1. It keeps our drinking water safe

Calgary’s drinking water supply is safe and clean. Water backflow device valves ( cross connection ) prevent contaminated water to go backward essentially preventing contamination of our drinking water and that is why this test is so important.

2. It’s the law

Water Utility Bylaw section 39.3e: “A test must be performed at the time the system is turned on at the beginning of each irrigation season.“

Potential water backflow appliances

Your home is full of appliances that use water. Some might be obvious on how they contaminate water, others not so much. The following fixtures and areas can have cross connection:

• Toilets
• infloor heating
• Laundry sinks connected with hose/s
• Boiler for in-slab or comfort heating
• Fire protection systems
• Hot tubs
• In-home water treatment system
• High-pressure washer

Homeowners must ensure no cross-connections exist on their property that could contaminate their water supply.  Click here to learn more about water backflow

Certified Cross Connection Testing

For a device to pass a City of Calgary cross connection test it must meet the following criteria:

1. The Device Must Be appropriate to the Static Pressure of the line it is installed on
2. The First Shut Off Must Close
3. Check Valve 1 must close tight in the direction of flow
4. Check Valve 2 must close tight in the direction of flow
5. The second Shut Off Must close

In Addition, the device must also be installed as per AWWA recommendations. An improperly installed device can result in the immediate failure of a device.

Testing is divided into three testing stages

1. The first test will determine the Static Pressure on the line that the device is installed on. Each Double Check Valve Assembly is rated for a certain pressure range, so we want to verify that the correct device is installed for that pressure range. The technician will use a pressure gauge to determine this reading.
2. The second test will determine if the First Shut off to the device can fully close off flow through the device and will also determine whether Check Valve 1 can close tight in the direction of flow. By using either Site Tubes or a Differential Pressure Gauge, the technician will simulate 1PSI of pressure against Check Valve 1. Check Valve 1 must close tight against 1PSI of resistance for a minimum of 2 Minutes to pass this portion of the test.
3. The Third test will determine if the Second Shut off is closed tight and determine whether the Second Check Valve can close tight in the direction of flow. Once again using either Site Tubes or a Differential Pressure Gauge the technician will simulate 1PSI of pressure against Check Valve 2.  Check Valve 2 must close tight against 1PSI of resistance for a minimum of 2 Minutes to pass this portion of the test.

If the device passes all three tests, the device can be returned to service. If the device fails, it must be serviced prior to the device being returned to service.