Installation, Commissioning and Testing of Backflow Prevention Devices
At Green Planet Plumbing we have found that many of our customers are unfamiliar with the problem of backflow. They unsure why and how it needs to be prevented, how backflow prevention testing works, and who can install, commission and test backflow prevention devices. With this in mind, we have compiled this blog to answer all the questions you never knew you had about ‘backflow prevention’.
What is Backflow?
Backflow refers to the unintended reverse flow of water from a property back into the drinking water supply. Backflow can occur if there is a drop in water pressure or the water pressure on a property is higher than the pressure at the water main, or via cross connections in a user’s premises and is considered a serious issue because it can result in used or potentially contaminated water entering the supply of drinking water.
What controls are in place for Backflow Prevention?
To safeguard public health and protect drinking (potable) water stores and its supply system, there are several controls in place to prevent backflow, including the requirement for backflow prevention devices being fitted to a sites’ connection to the water supply system.
The requirements for backflow prevention are set out in various laws, regulations, and standards, which may differ from one region to another, depending on the water supply authority.
When designing and building premises that are connected to mains water, the water supply authority generally requires that the plumber, building consultant or property owner complies with the backflow prevention measures set down in one, or all, of the following documents:
- Australia and New Zealand Standard for Plumbing and Drainage Part 1 (AS/NZS 3500.4:2021),
- The Plumbing Code of Australia
- Applicable standards of the water supply authority. For example, Hunter Water has a Connection Standard and a Site Containment Backflow Prevention Standard that must be adhered to.
What is a Backflow Prevention Device?
Every property that is connected to mains water is required to have an appropriate site containment backflow prevention device installed and maintained at the property’s boundary, immediately downstream of the property’s water meter. Backflow prevention devices must not be buried underground or installed in a chamber or pit – rather they should be easily accessible, to allow proper testing and maintenance.
The backflow prevention device is fitted to the mains fresh water supply pipe, generally on the water meter, to stop used or contaminated water flowing back into the water supply system. Backflow prevention typically utilises one of three methods:
- A one-way valve – a valve installed at specific locations within the property’s plumbing system where there is a risk of contaminated water flowing back into your system or into the drinking water supply.
- A break tank – a pressure-less and closed water tank, with an air gap. A break tank forms a buffer between the mains water supply and the property’s plumbing system, to prevent backflow into your system or the water supply.
- An air gap – an empty space between places where water might collect and fixtures that connect to your plumbing, such as faucets and valves.
There many kinds of backflow prevention devices within these categories, including:
- Registered break tank (RBT)
- Registered air gap (RAG)
- Pressure-type vacuum-breaker (PVB)
- Spill resistant pressure vacuum breaker (SPVB)
- Reduced pressure zone device (RPZD)
- Double check-valve (DCV)
- Reduced pressure zone detector assembly (RPDA)
- Double check valve detector assembly (DCDA)
- Single check-valve (testable) (SCVT)
- Single check valve detector assembly (testable) (SCDAT).
Which Backflow Prevention Device do I need?
The hazard rating determines the level of backflow protection device required. Many water authorities require that properties connected to their water infrastructure be inspected by an accredited person, risk assessed, and assigned a site containment hazard rating – low, medium, or high hazard.
The backflow plumber who installs and commissions the backflow prevention device must advise the property owner of the property’s backflow prevention requirements, install a backflow prevention device appropriate to the property’s hazard rating and advise the property owner of the maintenance and testing requirements for the device that has been fitted. The team here at Green Planet Plumbing are able to fit and test backflow prevention systems for you.
What is Backflow Testing?
Backflow testing is the testing carried out on backflow prevention devices installed to properties with medium to high risk hazard ratings. Initial testing is carried out when the device is first installed and commissioned for use, and then annually thereafter to confirm the device is operational and complies with AS2845.
Backflow devices are not infallible – they contain seals, valves and moving parts that are subject to wear and fatigue. Testing that the device is operating as intended is an important part of backflow prevention, along with checking that all water in the home is running in the right direction.
When testing your backflow prevention system, your accredited plumber will:
- Turn off the downstream shut-off valve.
- Wait a few minutes, to ensure the test will provide an accurate result.
- Check the pressure in the system with a special backflow testing kit.
- Register the results of backflow testing with the local water authority.
Please note that the customer is responsible for ensuring the site containment backflow prevention device is properly maintained and, where a medium or high hazard backflow device has been installed, is required to have the device routinely tested on an annual basis.
Who can install Backflow Prevention Devices?
Many smaller water meters, appropriate for installation at properties with a low hazard rating, are fitted with a simple, non-testable backflow prevention device (generally a dual check valve that is incorporated in the water meter). These simple backflow prevention devices may be installed by a licensed plumbing company, such as Green Planet Plumbing.
Larger water meters usually require a separate backflow device to be fitted by a licensed plumber or plumber with backflow prevention accreditation issued by a registered training organisation (a ‘backflow plumber’). Only accredited backflow plumbers are authorised to test and commission backflow prevention devices and to submit an approved test certification report with the water supplier, to verify that the device is effective.
Properties with an unmetered water connection must have a backflow prevention device appropriate to the property’s hazard rating installed and maintained by a licensed plumber at the point of connection to the water main (at the property boundary). Those properties with medium or high hazard backflow prevention devices installed to their unmetered water connection must be checked by an accredited backflow plumber annually.
Who can commission and test Backflow Prevention Devices?
After installation, a testable backflow prevention device must be commissioned and certified by an accredited backflow plumber within seven days, and the accredited plumber who initially tests and commissions the device must submit the test results to the local water authority.
Following installation and commissioning, the device must be tested annually by an accredited backflow compliance plumber. The results of these annual tests must be submitted to, and registered with, the local water authority, to confirm that the device is operational and compliant with the local water authority’s Site Containment Backflow Prevention Standard and Australian Standard AS2845.3:1993.
Contact Green Planet Plumbing for Backflow Prevention and Testing in the Newcastle region
Green Planet Plumbing have an unbeatable reputation as Newcastle’s most environmentally friendly plumbers, with timely and reliable service and the highest standards of workmanship. Our licensed plumbers and accredited backflow compliance testers are here to help you meet all your backflow prevention and testing requirements.
For peace of mind knowing that you are getting the best (and greenest) backflow prevention and testing services in Newcastle, contact Green Planet Plumbing Newcastle today by calling 02 4911 9402. Alternatively, send an email to firstname.lastname@example.org or complete our Enquiry form and one of our friendly team members will contact you back.