The following information relates to boundary backflows only; any testable backflow device on a fire service line and all internal/point of use backflows remain subject to the requirements of the Building Act, managed by Building Services on behalf of the Dunedin City Council.

A boundary backflow prevention device (also called a containment or point of entry device) is installed to protect the public water supply network from backflow from a customer’s property.  Water and Waste Services (WWS) manages the boundary backflow programme on behalf of the DCC in its role as water supplier, including annual testing of all boundary devices.  To support a safe drinking water supply network, WWS have been working on improvements to the programme of boundary backflow prevention.

Requirements for installing a new boundary backflow device

As boundary backflow devices are customer-owned they are subject to the Building Act. Before a new device is installed you will need to confirm there is DCC approval – either:

• a building consent – if the installation is part of a development and additional building work is proposed, or

• an exemption from the Building Act – where installing a boundary backflow device is the only building work being undertaken. The exemption form is available on our website .

A boundary backflow device must also be correctly located and installed. WWS are happy to discuss the specifics of an installation, or carry out a site visit, before a device is installed.

Installing a backflow as part of a new water connection

If you need a new “non-domestic” water connection as part of your building project, your Application for Water Supply must either confirm that a building consent has been granted for the installation of the backflow device (or that an application has been made), or include an application for an exemption as part of the water supply application.

Following installation

All newly installed boundary backflow devices require specific WWS approval, regardless of whether they have a Building Consent or an exemption. Final backflow device installation details must be promptly provided to WWS on the Notification of a New Boundary Backflow Prevention Device form, available on our website.

The WWS Backflow Technician will inspect the installation to confirm it meets our requirements, and will complete the initial test of the device. The new boundary backflow device will be added to the annual backflow testing schedule.

Testing of devices

WWS test all boundary backflow devices at least once a year. In specific circumstances, with a justified reason, WWS may agree in writing to the customer managing their own testing of a boundary backflow device through an IQP, with the test results submitted to WWS.

WWS are working with Building Services to ensure there is no overlap of testing of boundary backflow devices between a Building Warrant of Fitness compliance schedule and the boundary backflow prevention programme. All existing boundary backflow devices are being removed from the Building Warrant of Fitness compliance schedule as they are found.

For further information on boundary backflow, visit our website, phone the Water Bylaw Compliance Officer on 4774000, or email backflow@dcc.govt.nz.