Rotorua Lakes Council’s approval of a sewerage scheme that routed a pipeline past the culturally significant Lake Rotokākahi without properly engaging the lake’s governing body broke the law, the High Court has ruled.
Justice Kiri Tahana declared both the council’s 2020 decision to proceed with the Tarawera Sewerage Scheme and its later determination that earthworks near Rotokākahi could proceed without resource consent as unlawful.
Rotorua Lakes Council said it was committed to carefully considering all the High Court’s findings and would take time to review the decision in detail.
The ruling is a major victory for local iwi and hapū, who took the case to the High Court in December, after years of opposing the project and arguing the council failed to recognise the lake’s unique cultural and legal status.
However, Justice Tahana declined to order either decision be reconsidered, noting the roughly $30 million scheme had already been built and properties around Lake Tarawera are being connected to Rotorua’s wastewater network.
The legal challenge followed protests as construction approached the Rotokākahi area in early 2024. Work was paused before the council later obtained an injunction restricting obstruction of the project.
The Tarawera Sewerage Scheme was designed to improve the declining water quality of Lake Tarawera by replacing lakeside septic tanks with a reticulated wastewater system connected to Rotorua’s network.
The pipeline runs along Tarawera Rd, including a section beside the lake. As of July 31, 321 of 408 properties, about 80%, had been connected to the new system.
Rotokākahi is and remains Māori-owned and is governed by the Rotokākahi Board of Control.
The board challenged two council decisions in the High Court: the November 2020 decision to proceed with the scheme and a February 2025 determination that earthworks associated with the pipeline did not require resource consent.
Justice Tahana found the council overlooked planning rules recognising Rotokākahi’s cultural significance and requiring proper consultation before earthworks could proceed.
The judge said the council knew Rotokākahi was tapu (sacred, prohibited), Māori-owned and governed by the board, and had been alerted through a Cultural Impact Assessment that the board had “grave concern” about the preferred pipeline route passing the lake.
Yet there was “no evidence” the council had properly considered Rotokākahi or the significance of its decision to the board before approving the project.
“By not turning its mind to the Lakes A Zone document, there is no evidence the council turned its mind to Rotokākahi and the significance of its decision to the board,” Justice Tahana wrote.
Justice Tahana found the board should have been consulted before the council made its 2020 decision. Although the council later engaged with the board in 2023, she found that came after the critical decision had already been made.
The court also found the council acted unlawfully when it decided that earthworks required to install the pipeline could proceed without resource consent.
In February 2025, the council issued a notice concluding temporary excavation and backfilling associated with the project would have effects that were “less than minor” and could therefore be treated as a permitted activity.
Justice Tahana found the council misapplied the law and lacked evidence to conclude the earthworks’ effects were “less than minor”.
A Cultural Impact Assessment had warned that the project would involve “considerable earthworks in areas of cultural significance” and that it carried the potential to uncover sites of cultural or historical significance.
“Earthworks of short duration may still have significant cultural impact, depending on where the earthworks take place and what the earthworks uncover,” she wrote.
The board sought an order requiring the council to reconsider its original decision to proceed with the scheme.
Justice Tahana declined to do so, noting the pipeline had already been installed, houses were being connected and the council had since engaged directly with the board and was fully aware of its concerns.
She found reconsideration was likely to be futile while imposing further costs and delays and potentially affecting property owners relying on the scheme.
Instead, the judge said there was value in formally declaring the decisions unlawful, so the council would “take notice and care” before undertaking future activities within the Lakes A Zone.
“The lakes are precious taonga [treasures] of cultural significance,” she wrote, describing the board as an important reminder of the historic settlement that recognised Tūhourangi and Ngāti Tumatawera ownership of Rotokākahi, which remains Māori-owned and tapu.
Board chair Wally Lee said the judgment represented two serious findings against the council.
“We demand accountability and correction,” he said.
The board was considering the judgment and taking advice on future legal options.
“For us, this is not the end,” Lee said.
“Unlawful decisions affecting Māori-owned whenua [land] and a tapu ancestral landscape cannot be made without consequence.”
Protect Rotokākahi spokesman Te Whatanui Skipwith said the ruling vindicated more than two years of opposition to the project.
“The High Court has now confirmed that our concerns were justified,” he said.
Rotorua Lakes Council chief executive Andrew Moraes said the council recognised the cultural significance of the area and acknowledged the strongly held views that had been expressed throughout the project.
He said the council was committed to carefully considering all its findings and would take time to review the decision in detail to understand its implications and consider any appropriate steps.
LDR is local body journalism co-funded by RNZ and NZ On Air.
