Backflow Prevention

Backflow occurs when a contaminated source enters the water supply.

The contaminated source can enter through a cross connection with the drinking water supply. The water supply system is designed to ensure that water flows to your property under pressure, but if this pressure is not maintained, there is a chance that water could be drawn back into the Hunter Water supply system.

Water pressure can be affected when:

• There is a break in the watermain
• Water is being pumped from the main water supply during a fire
• A customer is using water at a higher pressure than the pressure supplied by Hunter Water
• Heavy water usage downstream causes a reduction in pressure upstream
• The water outlet on the property is higher than the watermain, causing a constant back pressure.

Potential problems from backflow

There is a risk to public health if there is a cross connection between your water and a contaminated source. If there is a pressure drop in the main, a vacuum could be created in the water supply system which, under certain conditions, creates a siphoning effect and draws liquid from a contaminated source back into the drinking water supply.

Preventing backflow

All new properties with a water connection will be serviced by a water meter with a domestic rated internal backflow device.

Hunter Water’s backflow prevention containment policy aims to improve the safety of Hunter Water’s supply by reducing the risk of contamination by backflow from connections to the water supply system. The policy also outlines requirements for fire services and standpipes and for new and existing properties.