Christchurch City Council will begin contacting property owners from next week to remind them about the importance of stopping water from back-flowing into the public drinking-water supply.
Letters will be sent out to mostly commercial and industrial property owners seeking information about types of backflow prevention devices installed on properties.
Backflow occurs when water flows backward from a property and into the public drinking-water supply network. It can happen if the pressure drops in the network and causes water – and potentially chemicals and other contaminants – to be sucked or pushed back into the public supply.
Council Head of Three Waters and Waste Helen Beaumont says while backflow events are rare, the risk to the public drinking-water supply is high.
“Backflow is one of the biggest risks to our drinking water and can seriously affect the quality and safety of our water, potentially causing serious illness, injury or even death.
“We’re committed to supplying safe, high-quality drinking water for everyone in Christchurch, and to make sure we can keep doing that, we need property owners’ help to ensure backflow doesn’t happen.”
Backflow prevention devices are a legal requirement for many commercial and industrial properties and are typically registered as part of the building consent process. The Council holds records for most properties with a backflow prevention device installed, however devices may also have been installed outside of the building consent process.
Where the Council doesn’t have a record of a device being installed on higher-risk properties, it is contacting those property owners to find out, Ms Beaumont says.
“As part of our revised Water Safety Plan and ongoing work to remove chlorine from the drinking water, we need to make sure we’re effectively managing the risk around backflow.
“Property owners are legally responsible for making sure the water on their property doesn’t contaminate the public drinking-water supply. This starts at the water meter and includes the entire property’s water system.
“Generally speaking, most residential properties don’t need a backflow prevention device, except where they may have in-ground irrigation systems, swimming pools, spa pools or dialysis machines. If in doubt, a registered plumber can advise further.”
Property owners are responsible for all costs associated with installing, operating, maintaining and testing a backflow prevention device.
Where at-risk properties are without one, the Council will be asking owners to apply for a building consent and to have a device professionally installed.