Understanding Backflow and Backflow Prevention
What Is Backflow?
Water should normally travel from the water supply network into a property. Backflow occurs when water moves in the opposite direction and flows back towards the clean water supply.
Backflow can generally occur in two ways:
- Back-pressure: Pressure within the property becomes greater than the incoming water supply pressure.
- Back-siphonage: A reduction in supply pressure causes water to be drawn back from the property.
If the downstream water has been exposed to chemicals, waste, irrigation systems, equipment or another potential contamination source, reverse water flow can create a risk to the clean water system.
What Does a Backflow Prevention Device Do?
A backflow prevention device is installed to reduce the risk of contaminated or potentially contaminated water flowing back through a connection and entering the clean water supply.
The type of device required depends on factors such as the identified hazard, plumbing system design and relevant requirements for the property.
Some backflow prevention devices are testable and contain internal components that need to operate correctly to provide the intended protection. A device may be installed but still fail to perform as required if components are damaged, obstructed, worn or deteriorated.
Which Properties May Need Backflow Protection?
Backflow protection may be relevant across a wide range of properties and plumbing systems, including:
- Commercial properties
- Industrial facilities
- Mining and regional sites
- Strata complexes
- Irrigation systems
- Fire services
- Properties using chemicals or specialised equipment
- Sites using non-potable water
- Residential properties with a particular cross-connection risk
- New developments and plumbing upgrades
This is not a definitive compliance list. Backflow requirements should always be confirmed for the specific property, plumbing system and installation.
Backflow Testing, Servicing and Property Requirements
What Happens During Backflow Testing?
A licensed plumber or backflow tester will identify the backflow prevention device, review the installation and carry out the applicable test using suitable testing equipment.
A typical backflow testing service may include:
- Confirming the property and device details
- Inspecting accessible parts of the installation
- Isolating the device where required and safe
- Testing the relevant internal functions of the device
- Recording the test result
- Identifying whether servicing, repairs or replacement may be required
- Providing relevant service documentation
The exact testing process will depend on the type of backflow prevention device, the installation and the conditions at the property.
What Can Cause a Backflow Device to Fail a Test?
A backflow prevention device contains components that can deteriorate, become obstructed or be affected by the conditions surrounding the plumbing system.
Possible reasons for a failed backflow test can include:
- Worn internal components
- Debris or scale inside the device
- Damaged seals or springs
- Corrosion
- Long periods without servicing
- Incorrect installation
- Isolation valve problems
- Damage caused by site conditions
- Unauthorised modifications to the plumbing system
A failed backflow test does not automatically mean the entire device needs to be replaced. The tester can assess the condition of the device and determine whether servicing is practical and whether suitable replacement components are available.
How Often Does a Backflow Prevention Device Need Testing?
Backflow testing frequency depends on the device, property and applicable authority or regulatory requirements. One testing schedule should not be assumed to apply to every backflow prevention device.
Property owners and managers should check the documentation associated with the property or confirm the applicable requirements with the relevant authority. Driftline Plumbing Services can also review the available device and property information when arranging a backflow service.
Can a Property Owner Test a Backflow Prevention Device?
Testable backflow prevention devices require suitable equipment, technical knowledge and the relevant licence or accreditation. Property owners should not dismantle, adjust or attempt to test a device themselves.
Property owners and managers can still carry out basic visual observations. Visible leakage, corrosion, damage, restricted access or unauthorised changes to surrounding pipework should be reported to a suitably qualified plumber.
What Backflow Records Should Property Managers Keep?
Maintaining clear backflow records can make ongoing testing and servicing easier, particularly for commercial properties, strata complexes and sites with multiple devices.
Useful backflow records may include:
- Property address
- Device location
- Device type and identification details
- Installation date, if known
- Previous backflow test reports
- Servicing and repair history
- Photographs of the device and installation
- Relevant authority correspondence
- Site access instructions
- Contact details for the responsible property representative
For properties with several backflow prevention devices, maintaining a device register can help reduce missed testing or servicing requirements and make it easier to compare previous results.
Backflow Installation, Planning and Professional Services
Backflow Planning for New Plumbing Projects
Backflow requirements are best considered during the plumbing design and planning stage rather than being addressed after other building elements have already been installed.
Early planning can help account for:
- Appropriate backflow device selection
- Accessible installation locations
- Isolation requirements
- Drainage for device discharge where relevant
- Protection from physical damage
- Future testing and maintenance access
- Coordination with landscaping, walls, cabinetry and equipment
- Documentation and project handover requirements
Where backflow protection is considered too late in a project, the remaining installation location may be less practical, harder to access or more difficult to coordinate with surrounding building elements.
Why Use a Licensed Backflow Testing Service?
Using a suitably licensed backflow service provides a clear record of the condition and test result of the device while ensuring any recommendations are based on the actual installation.
Driftline Plumbing Services holds backflow licence BF5553 and provides backflow testing, servicing and installation across Perth and Western Australia.
Book Backflow Testing with Driftline Plumbing Services
If you need backflow testing, servicing or installation, provide Driftline Plumbing Services with the property address, number of devices and any previous backflow reports available.
Our team can review the information provided, confirm the next step and advise what access or documentation may be required before attending the property.