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WATER
Central Interceptor: Auckland Wastewater Tunnel
Watercare · Auckland
Auckland's 16.2km, 4.5m-diameter wastewater tunnel from Grey Lynn and Point Erin to the Māngere treatment plant, cutting wet-weather overflows into the Waitematā and Manukau harbours by about 80%. Cost about $1.67b, up from $1.2b. The northern section was commissioned on 20 July 2026, making the full tunnel operational.
✓
Delivered
This project is complete.
Data current as at 16 Sept 2026, when the pipeline was last checked against its source.
Key facts
- Region
- Auckland
- Sector
- Water
- Status
- Complete
- Estimated value
- $1.7b
- Indicative completion
- 2026
- Funding status
- Fully Funded
- Lead organisation
- Watercare
- Election risk
- Safe
Election risk assessment
Critical utility infrastructure, fully funded by Watercare and now complete.
Government priority alignment
HIGH: Critical three-waters infrastructure reducing harbour overflows.
Recent changes
- 2026-W37Major New project added: Central Interceptor: Auckland Wastewater Tunnel (Complete, $1.7b).
Chronology
- 2019Main construction begins
- 2025Southern section commissioned; 16.2km tunnel breakthrough
- 2026Northern section commissioned (20 July); full 16.2km tunnel fully operational
Source
Watercare: Central Interceptor ↗ · Watercare: Central Interceptor fully live (20 Jul 2026) ↗ · Watercare: Central Interceptor project budget increase (Dec 2023) ↗