FAQs

Backflow is an unintended condition which can allow drawn water to flow back into a water supply creating a pathway for contaminated or used water to enter the clean water supply. It is caused by the pressure differential in water supply networks. The outcome of a backflow event can range from discolouration through to death or other serious health issues

Taumata Arowai (the water regulator of Aotearoa New Zealand), requires Council to create and implement a backflow prevention programme to protect its water supply from contamination. 

The proposed Backflow Prevention Policy 2024 will be enabled through Council’s Water Supply Bylaw. Council’s current Water Supply Bylaw refers to the Heath Act 1956 to enable the regulation towards backflow prevention. However, those sections of the Health Act 1956 in relation to backflow have been repealed and are now enabled through the Water Services Act 2021. 

We are taking this opportunity to amend the backflow prevention section of Council’s Bylaw to reflect this legislative change to meet the legislative requirements under the Water Services Act 2021 and Taumata Arowai.

Council is proposing changes intended to add clarity to Council and Customers’ backflow prevention obligations and strengthen the compliance provisions related to backflow in the Bylaw.  

We are also adding some key definitions:

Backflow prevention device means a valve installed on a water supply to prevent backflow from occurring and safeguard the water supply system.

Essential Works means work required to be done under urgency and which is necessary for the continued and/or safe operation and protection of the public water supply.

Potable means water that is safe to drink and that complies with the drinking water standards.

A Backflow prevention device is a valve installed on a water supply to prevent backflow from occurring and safeguard the water supply. These include:

• dual check valves (non- testable);
• double check valves (testable); and

reduced pressure zone devices (testable). 

A backflow prevention device is essential to protect clean and potable water supply network from contamination from a backflow event. 

Boundary backflow prevention devices are backflow prevention devices that are installed at the boundary of a property to prevent backflow from a property from entering into the public water supply network. It is defined in the proposed policy as “any backflow prevention device located at or near the point of supply as defined by the Council, usually as close as is practical to the property boundary”.

Depending on the nature of the backflow prevention risk identified under Appendix 1 of the proposed policy, Council may: 

• install a boundary backflow prevention device and require the customer to reimburse Council for the cost of installation, maintenance and ongoing testing of the device; or 
• require the customer to install, maintain, and test a boundary backflow prevention device that incorporates a verifiable monitoring system in accordance with any requirements imposed by the Council.

use a combination or any hybrid of the two options above so as to achieve suitable protection of its water supply and the ongoing testing and maintenance of boundary backflow prevention devices.

All domestic non-testable backflow prevention devices are to be paid by the Customer. 

Irrespective of ownership of whether the device is owned by Council or by the customer, all testable boundary backflow prevention devices must be tested annually.

The testing shall be undertaken only by an Independently Qualified Person (IQP) approved for backflow prevention device testing (SS7) by the South Island IQP Panel.  All testing must be carried out as per the New Zealand Backflow Testing Standard 2019: Field testing of backflow prevention devices and verification of air gaps or AS/NZS 2845.3. 

Council will administer the compliance and enforcement of the proposed policy in accordance with the amended Water Supply Bylaw. 

 In the event of a breach of the backflow prevention section (section 8.10) of Council’s Water Supply Bylaw, Council will notify the customer of the breach and will take all necessary steps to remedy it. If the breach persists for more than one week, Council may reduce the water flow rate to the customer without further notice. Full water service will be restored only after the appropriate fee is paid and the breach is resolved to Council’s satisfaction. Additionally, if Council needs to intervene or carry out remedial work, the cost will be borne by the customer. 

A breach also constitutes in relation to any tampering, modifying or circumvent any boundary backflow prevention device without written approval from Council, they will also be in breach of the bylaw.

Council will monitor compliance through inspections, the annual Building Warrant of Fitness process and Request for services. 

No, the Backflow Prevention Policy, and the Proposed Changes to the Water Supply Bylaw only affect those connected to the Invercargill City District Water Supply.

Yes. Internal backflow preventers are required by the Building Code to protect users inside the building from potential contamination. The backflow preventer at the boundary serves a different purpose and is there to protect the city’s water supply.

At this stage we are focusing in high and medium risk properties, and the majority of residential properties are considered very low risk. The criteria for needing one is related to the use of the property and the risk this poses to our water supply. If you think this may affect you, please get it touch via Policy@icc.govt.nz and we can direct your query to the right team.

If you use your property for another use, other than just residential, you may need to have a boundary backflow prevention device fitted. The type will depend on the nature of the business and whether it poses a risk to the city’s water supply. Example of home businesses that may be affected include but are not limited to home hairdressers or those that run a commercial kitchen with a commercial dishwasher

Council’s 3-waters team can give advice on individual property requirements. You can email at backflow@icc.govt.nz

If these documents are adopted by Council, they will come into effect on 1 December 2024

If you have any questions, you can contact the policy team on 03 211 1777 or via email to policy@icc.govt.nz

If you have a water supply concern concern, you can log a request for service via our customer services team, you can do this:

• In person at Te Hīnaki – Council Administration Building or Bluff Service Centres, 
• Via phone by calling (03) 21 11777

Online at My Invercargill: icc.govt.nz

You make your submission on the draft bylaw through letstalk.govt.nz and you can drop in your submissions at the Te Hīnaki Civic Administration Building, the Invercargill Public Library and the Bluff Service Centre.  

Submissions close 18 October 2024