Backflow occurs when water flows in the opposite direction to what it is expected to flow. The water is intended to flow in one direction and for a some other reason it flows in the in correct direction.
A drop in water pressure normally causes backflow. Some of the causes for this can be water pipe bursts, pipes freeze or unexpectedly great demand on water systems. This ultimately creates backward pressure in the water supply system. When a backflow occurs, reduced pressure may allow water from the ground, storage or other sources to enter the system. One of the biggest concerns is that this allows drinking that we drink to be contaminated via a cross-connection.
A proper device will ensure water flows safely by automatically trapping water that begins to flow in the incorrect direction. This prevents water from a property being drawn back into the main drinking water supply and causing cross-connection.
The risk ratings of a home or office will determine what type of backflow device will need to be installed. Homes and buildings are classed as low, medium or very high risk. A professional plumber can confirm the risk rating of your property.
A proper backflow assembly unit will have test cocks and shut off valves. Backflow devices must be thoroughly tested when they are installed, relocated or repaired. Devices must also be tested regularly to ensure they are in proper working order.
Victoria Water States the following about backflow:
Each backflow prevention containment device must be tested on a regular basis. This is a condition of connection to the water supply. It means that the device is maintained and continues to operate correctly. The test will ensure the drinking water supply is protected from backflow.
If a device is defective or faulty, it may:
- not prevent a contaminated source entering the drinking the water supply
- cause water to be wasted through leaking devices
- impact on the water pressure supplying your property
An accredited licensed plumber will need to test all of your devices. After testing your devices your licensed plumber will submit his report within 2 days on the Victoria water website stating if the device is installed correctly and if it has passed or failed the test. The plumber will give you a copy of the Prevention Device Inspection and Maintenance Report. If a valve fails the test and is not repaired or replaced Victoria water can disconnect you from the main water supply.