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For most of us, access to clean, safe drinking water is something we take for granted when we turn on the tap. But what if contaminants from an irrigation system, fire sprinkler system, or industrial process could potentially flow backwards into your property’s drinking water supply system?
This dangerous scenario is called backflow, and preventing it is critical for safeguarding potable water supply.
At Woden Valley Plumbing, we are committed to helping clients understand what backflow is, why preventing it matters, and how to protect your water supply through high-quality backflow prevention devices and services. You can trust us to manage your backflow prevention needs.
What is Backflow Prevention and Why is it Important?
Backflow is defined as the unwanted reverse flow of contaminants into the drinking water system through cross-connections. It occurs when back pressure or siphonage overcomes the normal flow direction in plumbing systems.
Backflow can introduce bacteria, chemicals, or other hazardous substances into water systems to keep us healthy.
No one wants polluted water coming out of their tap.
Some reasons backflow occurs include:
- Back pressure from pumps, boilers, pressure vessels
- Undersized plumbing lacking air gaps
- Cross connections with non-potable water sources
- Improper plumbing installations
To safeguard public health, laws and plumbing codes now mandate an appropriate containment backflow prevention device in many commercial, industrial, irrigation, fire services, and even some residential settings.
Having provided exceptional plumbing services in Canberra since 1997, our team at Woden Valley Plumbing wants to partner with you to ensure full compliance and – most importantly – safety. Contact us today to learn about your options for certified backflow prevention testing, installation, and maintenance.
What is a Backflow Device?
A backflow prevention device (often shortened to “backflow device” or “backflow preventer”) is a mechanical valve arrangement that automatically blocks any reverse movement of water. Inside the body of the valve are one-way check mechanisms and, in higher-risk models, a relief zone that dumps water to atmosphere if backward pressure builds.
The moment flow tries to reverse, the checks snap shut or the relief port opens, keeping the dirty side physically separated from the clean side.
Types of Backflow Prevention Devices and Choosing the Right Solution
Depending on the your hazard rating, the specifics of your plumbing system, and relevant building codes, different types of backflow preventers are warranted.
At Woden Valley Plumbing, our backflow plumbers have in-depth expertise with all devices certified for backflow prevention in the Canberra region. We stay current on the latest standards and installation best practices so we can educate you on your options and prevent contaminated water.
Protecting your water supply is our top priority.
What is a Hazard Rating?
There are three hazard ratings in Australia:
| Hazard rating | What it means for the water supply | Everyday examples | Minimum device the water authority will accept* | |
| Low hazard | The connection might create a nuisance (bad taste, odour, discolouration) but cannot injure anyone or make them sick. | Domestic garden taps- Evaporative air-conditioning make-up lines- Ordinary dishwasher hose | In many homes the 20 mm or 25 mm meter already has an internal dual-check cartridge, so nothing extra is needed. Larger or commercial meters must add a dual-check valve (non-testable) immediately after the meter. | |
| Medium hazard | Backflow could endanger health (cause illness) but is unlikely to be life-threatening. | Irrigation that sprays fertiliser or manure- Commercial laundries- Apartment fire services that use booster pumps | A double-check valve assembly (DCVA) that can be field-tested each year. | |
| High hazard | Backflow could cause serious injury or death because toxic, infectious, or radioactive substances may enter the mains. | Hospitals and pathology labs- Chemical dosing or pesticide mixing points- Trade-waste pits, abattoirs, mortuaries | A reduced-pressure-zone device (RPZD) or an air gap with an overflow to drain. |
How the Rating is Worked Out
- Site inspection: A licensed backflow plumber (or the water authority) looks at every way your plumbing could feed contaminants back toward the meter.
- Apply the Standard: They match each connection to the definitions above. If more than one process is on site, the highest hazard present sets the rating for the whole service.
- Select the device: Once the rating is locked in, the plumber chooses the appropriate valve and files a compliance notice with the authority.
Common Types of Backflow Prevention Devices
Air Gap
The air gap is the simplest mechanical backflow prevention device, providing a physical separation between the drinking water outlet and the receiving vessel’s flood-level rim. While effective, air gaps can be prone to bypass through splashing and require adequate drainage.
Reduced Pressure Zone (RPZ) Valve
RPZ valves, with their two independently operating check valves, are well-suited for high-hazard backflow device installations. However, they require regular testing and maintenance. RPZ valves protect against both back pressure and back siphonage.
Double Check Valve Assembly (DCVA)
Also equipped with two positive-seating check valves, DCVAs offer protection against only backflow caused by backwater pressure. Regular testing is still essential to ensure performance. These are common in fire sprinkler systems.
Atmospheric Vacuum Breaker (AVB)
AVBs allow air to enter the backflow device to prevent siphoning and backflow. As non-testable devices, they can only be used to isolate hazards under specific conditions.
Pressure Vacuum Breaker (PVB)
With more moving parts than an AVB, PVBs offer testable protection against back siphonage for continuous pressure conditions. Proper installation is vital for this backflow prevention device to function correctly.
Choosing which type of backflow prevention device is right for your water supply depends on weighing factors like the associated risk, pressure conditions, complexity, and cost. Our experts at Woden Valley Plumbing can simplify this decision and ensure your safety. Contact us today.
Where Backflow Prevention Is Needed: Protecting Vulnerable Systems
While no property is immune to the risk of potential contamination, some buildings and facilities are more vulnerable than others. Understanding the most critical applications for a certified backflow prevention device is vital.
Some common situations where it’s an absolute necessity to have an effective backflow prevention device installed include the following:
Residential Applications
Even residential customers can sometimes benefit from backflow devices for their homes. Irrigation systems, swimming pools with piping connections, and properties with onsite water features may require atmospheric or pressure vacuum breakers for their water supply system.
Commercial and Industrial Applications
Businesses and factories with complex plumbing systems using hazardous chemicals, processed water, or holding tanks typically need advanced protection like RPZ valves or DCVAs.
Fire Protection Systems
Nearly all fire sprinkler systems need to double-check valves at a minimum to prevent backflow contamination risks. Reduced water pressure devices may also be warranted under certain conditions to offer maximum safety.
Irrigation and Lawn Sprinkler Systems
All underground irrigation and lawn sprinkler systems connected to your main water supply should have atmospheric or pressure vacuum breaker devices installed to safeguard your drinking water.
Backflow Prevention Installation: Partnering with the Experts
Getting prevention devices correctly installed is critical for their functioning and your ongoing safety. Our team at Woden Valley Plumbing has the experience to do the job right the first time.
- All our plumbers are fully licensed in the ACT region
- We supply only approved backflow prevention products from reputable brands
- You get transparent quotes with no hidden charges
What Does The Device Installation Process Look Like?
Initial Consultation
We assess your current plumbing system, intended uses for water supply, and potential hazards. This allows us to determine the optimal backflow protection devices for your application. We can advise you on all code compliance needs as well.
Permit Applications
Where mandated, we submit necessary permit paperwork and plans to authorities on your behalf so you avoid headaches
Precision Installation
With years of experience, our licensed plumbers expertly install approved backflow preventers according to all specifications from the manufacturer and the latest codes. Correct valve placement is assured.
Backflow Prevention Testing and Reporting
We conduct leak tests, confirm proper operations of moving parts, test backflow prevention devices, and any other mandated checks before generating installation reports for your records and submission to regulators.
Note: Australian water utilities require your backflow prevention device to be certified every 12 months by a licensed, backflow-endorsed plumber if there is a high-or medium-hazard connection (e.g.irrigation with fertiliser injections, commercial kitchens, hospitals, and chemical dosing lines)
Contact Woden Valley Plumbing for Your Backflow Prevention Needs
With over two decades of experience providing exceptional plumbing services to Canberra homes and businesses, Woden Valley Plumbing has the expertise to handle all your backflow prevention requirements.
To learn more about how we can protect your water supply through certified backflow solutions, please contact us today at (02) 6288 5123 or info@wodenvalleyplumbing.com.au.
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