Backflow Prevention

One of the biggest risks to our water supply is backflow. This is caused when water pressure drops in the water distribution system causing water to flow in the opposite direction from residential or commercial premises back into the public water supply network. Because both homes and businesses use chemicals and other potential contaminants, backflow can be a major threat to the health and wellbeing of residents and visitors.

In the Christchurch City Council district, the backflow risk arising from the activities on a premises is assessed and it is mandatory that an appropriate backflow prevention device is installed at the point of water supply. Dewaters Plumbing & Gas are independent qualified persons (IQP) that are registered and qualified to undertake this work.

Most commercial and industrial properties are required to have a minimum of medium hazard protection at the boundary to protect the main water supply. The installation of this device is a condition of supply and is the responsibility of the property owner.

For homeowners, the Christchurch City Council provides low level protection at the point of connection to the public water supply. It does not protect water from hazards that can occur within the home. Sometimes the level of protection provided at the water connection may not be sufficient – especially if certain activities such as spa baths, swimming pools or dialysis machines exist within the premises. Protection within the premise must be carried out under Section G12 of the New Zealand Building Act 2004.