Western Bay council to replace leaking Katikati wastewater pipeline

The Katikati wastewater outfall pipeline has experienced several breaks in recent months, requiring urgent repairs. Photo / Western Bay of Plenty District Council

Western Bay of Plenty District Council is pushing ahead with plans to replace the Katikati wastewater outfall pipeline, following a series of failures that have raised environmental and community concerns.

The 12km pipeline, buried 3m beneath Tauranga Harbour, broke four times in the past six months alone.

Council general manager infrastructure Brad Singh said in a statement issued by the council that each repair was “complex, costly and high-risk”.

A map of the current Katikati Wastewater Disposal system. Photo / Western Bay of Plenty District Council

“We’ve reached a point where a long-term solution is essential.”

The Katikati Wastewater Treatment Plant discharged treated wastewater via the ocean outfall pipeline off Matakana Island.

While the pipeline was designed to discharge offshore, leaks along the route meant treated wastewater could enter the harbour in uncontrolled locations, prompting urgent repairs.

The current discharge consent was granted in 2018 for a 20-year term under national resource management rules.

It expires in 2038 and requires the council to confirm a future disposal method by 2026.

The council statement said it had been working on a long-term solution that would protect the harbour, meet environmental standards and respect cultural values.

Tangata whenua and key stakeholders helped shape an approach that retained the ocean outfall but introduced higher treatment standards.

This option would be consulted on with the community early next year as part of the 2027–2037 Long Term Plan process.

The wastewater outfall project was also being considered alongside the Katikati Spatial Plan, which looked at the future of the wider area, including infrastructure, environment and community needs.

“We know the recent leaks have caused concern, and that’s why we’re acting now,” Singh said.

He said the council needed to balance installing a future solution in a reasonable timeframe, while still giving the community time to provide feedback on the proposed option.

Funding for the project had already been included in the council’s current Long Term Plan, with significant investment earmarked for the pipeline replacement.

The current Annual Plan also included budgets for investigations and preparatory work.

The council confirmed it had begun design and consenting work, supported by early engagement with key stakeholders.

In the meantime, it continued to manage risks through enhanced pressure monitoring, flow meters and additional storage solutions to minimise the chance of further leaks.

“This is about future-proofing our infrastructure while respecting the harbour and the communities who rely on it,” Singh said.

The Annual Plan includes $100,000 for “Katikati wastewater disposal future directions”.

The current Long-Term Plan, which began in 2024, included $68 million for Katikati wastewater outfall.

The plan said sections of the ocean outfall pipe were “failing much earlier than the pipe design life”, and had failed twice recently.

“… Early estimates suggest the design, consent and installation of new disposal options for the Katikati [wastewater treatment plant] will cost approximately $68m.”

Funding was also included in the plan to “allow for breaks in the outfall pipeline until a suitable disposal method can be built”.

The average maintenance over 10 years was expected to be $740,000 a year.

The plan noted “potential compliance implications or prosecution risk if treated wastewater leaks continue”.

The council’s website said the options being considered were disposing treated wastewater over land through irrigation or wetland treatment centres, and upgrading the ocean outfall “if land options are not feasible”.