By Elliot Olsen
Lower North Island & Design Lead
Every water pump in Auckland used to deliver water from the Aquacomb tank system into the house should have what is called a backflow prevention valve installed.
What is Backflow?
Backflow is the unwanted process of water flowing back into the public water supply due to a difference in pressure. When the flow of water reverses, harmful bacteria and/or chemicals can enter the water supply which can affect the quality and safety of drinking water.
Backflow is typically caused in two different ways:
- Back-siphon: When water supply falls below atmospheric pressure which lets water be drawn back through pipe work. For example, if a water pipe is broken whilst water is turned off, the flow of water exiting through the creak could siphon contaminated water into the pipe work.
- Backpressure: This occurs when the pressure within any water service and a higher pressure within any vessel or pipework it is connected to differs.
What is Backflow Prevention and how is it achieved?
Backflow prevention is the process of ensuring water flow is not reversed and potentially harming the public potable (drinking) water network.
The New Zealand Building Code G12.1 states:
“The objective of this provision is to– (a) safeguard people from illness caused by contaminated water”.
In addition, the performance provision requires “G12.3.1 Water intended for human consumption, food preparation, utensil washing or oral hygiene must be potable.”
Backflow prevention can be achieved by installing a special backflow prevention valve on the water pump.
The testable backflows valves on our Plug N Play pumps are cleverly designed with two separate backflow prevention valves inside it, which can both be tested independently of each other using a specialised piece of testing equipment. This way if one valve starts to wear out, the valve can be replaced before they both fail.
What Forms of Backflow Prevention Are There?
The three common types of backflow prevention are:
- Air gap
- Dual check valve
- Testable dual check valve
These devices are selected depending on the potential hazard of the environment.
All pump solutions from Watersmart include a testable backflow prevention device.
Image: Testable double-check valve on Watersmart Plug N Play Pump
Why is Backflow Prevention Important?
Backflow is a major risk to the public water supply and without prevention, can harm the quality of drinking water.
Auckland Council takes backflow prevention seriously in order to protect the health of Auckland residents. Not only do they require a backflow prevention valve to be installed, but it must also be inspected annually, with the results sent to Auckland Council to be recorded. All pumps with testable backflow prevention devices are required to be tested and tagged by a person deemed qualified by a Territorial Authority who is IQP Trained (Independent Qualified Person), such as the pump experts at Watersmart. This is to ensure the valve continues to work year in and year out and can be replaced if it starts to degrade.
Have questions? Talk to our friendly team today.
