Central Interceptor

A super-sized wastewater tunnel that will reduce overflows

Construction of the Central Interceptor is well underway

Over the next four years we’re building the Central Interceptor tunnel to help make Auckland's waterways cleaner. The Central Interceptor will run underground from Grey Lynn to our Māngere Wastewater Treatment Plant. It will have several link sewers and shafts along the route for collecting and transferring wastewater into the tunnel.

Our contractor Ghella Abergeldie Joint Venture (GA) is building the Central Interceptor. GA has more than 150 years’ experience with tunnelling and wastewater projects of this size across the globe.

Once completed, the tunnel will be 14.7 kilometes in length, the longest bored wastewater tunnel in New Zealand. At 4.5 metres in diametre, it will be high enough to fit a giraffe and wide enough to fit four rhino side by side.

To find out more about the project, click here to watch our video and see how the Central Interceptor will make Auckland a better place to live.
Benefits to you

Benefits to you

Find out how the Central Interceptor will benefit your community. 
Staff check the equipment at a water treatment plant

Community events

Information about our community days and education programme 
Consent Documents

Consent Documents

All the consent documents associated with the project. 


Our answers to frequently asked questions associated with the project. 

Key facts

All the facts and figures about the Central Interceptor project. 

Meet the team

Get to know the people who are working on New Zealand's longest tunnel. 


All the latest news, newsletters and media clippings about the project. 

Our sites

Find out what's happening at our sites across Auckland. 

Progress in pictures

A picture gallery of the project as it takes shape. 
Image of a piece of the Central Interceptor tunnel boring machine being lowered into the main shaft

Keep up with us on social media

Facebook: WatercareNZ
LinkedIn: Watercare Services Limited

On Friday 30 July, our 190-metre Tunnel Boring Machine (TBM) Hiwa-i-te-Rangi will be launched at our Māngere site and head north digging a supersized wastewater tunnel that will help prevent wet weather overflows and clean up central Auckland beaches. The engines will be turned on for an official ‘see you later’ ceremony, and the public will be given the chance to wave goodbye on Sunday (1 Aug). Along her 14.7km journey to Grey Lynn, 15 of our crew will be working underground at any one time. Take a listen to our Executive Programme Director Shayne Cunis speaking with Kathryn Ryan on RNZ about this exciting engineering project.