Central Interceptor - ISCouncil

Central Interceptor

Project Details

  • Project Owner: Watercare Services Ltd
  • Rating Type:Design
  • Location: NZ
  • Stakeholders:

This project by Watercare Services Ltd has achieved a V 1.2 Design Leading Rating .


The Central Interceptor is New Zealand’s largest wastewater tunnel project, consisting of a 14.7 km main tunnel, multiple shafts, a major pump station and substantial wastewater network infrastructure. It is located in Auckland and will run underground from Grey Lynn, to Watercare’s Māngere Wastewater Treatment Plant.

A Tunnel boring machine will be employed to build the underground tunnel, which lies between 15-110 m below the surface and has an internal diameter of 4.5 m. Most of the construction will be underground and includes structures at the connection points such as access shafts, drop shafts, flow control structures, overflow structures, grit traps, air vents and air treatment facilities. The construction period for this project is expected to be 6 years.

The Central Interceptor will reduce combined wastewater and stormwater overflows that currently flow into urban waterways and beaches. It will also duplicate a critical section of our network under the Manukau Harbour.


  • Rating Type Water
  • Practical Completion January 2025
  • Jurisdiction New Zealand
  • States NZ
  • Suburb Auckland
  • Assessor Olivia Philpott
  • Other Stakeholders Ghella-Abergeldie Joint Venture, Jacobs



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