14 Jan 2026: treated wastewater pipe, lake weed

Media: Local Democracy Reporter

Topic: Lake weed

Enquiry

NOTE: this enquiry was also sent to BOP Regional Council

I’m following up on the recent lake weed wash-up at the Rotorua lakefront and the ongoing discussion around funding and management responsibilities.

Just looking to some answers to the following questions if possible.

• What was the final cost to Rotorua Lakes Council?
• What advice has council provided to central government about the adequacy of current lake weed funding, and how long has it been raising those concerns?
• Has there been any response from Minister Penk to correspondence from both council mayors late last year? If so, what did that entail?
• How does council interpret LINZ’s funding criteria, particularly the emphasis on protecting weed-free lakes, when applied to Rotorua’s already heavily impacted lakes?
• Are you concerned about the impact of further lakeweed, particularly for the lakefront and surrounding businesses?

I’m working to deadline and would appreciate a response by 10am tomorrow (Weds 14), if possible.

Response

From Mayor Tania Tapsell:

“Our message is clear, Rotorua lakes need fair funding from Government to address significant lake weed issues.

“Councils, iwi and locals have worked hard over many years to identify and deliver solutions and the fact is we're not being funded enough to deal with lake weed which is actually an introduced aquatic pest.

“There's been so much positive public and private investment around our Lakefront, we can't continue to have major wash-ups of lake weed because it has a huge impact on the quality of life for many local residents, trading for businesses, and it damages the experience for visitors.

“I've expressed our frustration at the significantly higher levels of funding allocated to other lakes across New Zealand for similar issues. This is grossly unfair and doesn't meet the legal treaty settlements that the Crown have to manage lake weed in Te Arawa lakes.

“Following our letter to Minister Penk, we met with LINZ representatives and our local leaders to discuss the best way forward and will continue to put pressure and accountability on Government agencies to support us to have clean lakes that we can all enjoy.

“We won't stop advocating until an appropriate solution is in place to protect Rotorua’s environment, reputation and economy from the impact of lake weed.”

From RLC organisation:

Total cost to Rotorua Lakes Council for clean-up of the most recent lake weed stranding is $58,646 + GST.

From BOP Regional Council:

What was the final cost to BOP Regional Council?

Regional Council contributed $66,000 to the response.

What advice has council provided to central government about the adequacy of current lake weed funding, and how long has it been raising those concerns?

The Regional Council has long maintained that Central Government funding for lake weed management is insufficient and has raised these concerns numerous times with Land Information New Zealand (LINZ), the government agency responsible for managing lake weeds attached to the lakebed in the Rotorua Te Arawa Lakes.

Has there been any response from LINZ or Minister Penk to correspondence from both council mayors late last year? What did that entail?

Staff are unaware of any formal responses from LINZ or the minister to the Regional Council.

How does council interpret LINZ’s funding criteria particularly the emphasis on protecting weed-free lakes, when applied to Rotorua’s already heavily impacted lakes?

LINZ have a responsibility under the Te Arawa Lakes Settlement Act 2006 to manage lake weeds attached to the beds of the Rotorua Te Arawa Lakes. Our main concern is that they are not fulfilling those obligations and this is leading to flow on effects like weed wash-ups.

Does council agree with the view that large-scale weed control in Rotorua is no longer realistically achievable, and what evidence or analysis underpins its position?

Regional Council does not agree with this position and maintain that with the right level of investment and resourcing, large scale weed control can be achieved. Regional Council and its partners have been working on a lake weed business case and presented it to the Rotorua Te Arawa Lakes Strategy Group on 22 August 2025. Notes from the meeting can be found on the BOPRC website under agenda item 6.1 - LINK

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Media: Local Democracy Reporter

Topic: Treated wastewater pipe at treatment plant

Enquiry

Just following up with some questions about the wastewater pipe leak from November.

Some questions below.

• Has the cause of the pipe break now been established and if so can you give any more details on how it came to be damaged?
• Was the pipe subject to any routine monitoring or testing prior to this failure, and if so, did that reveal any early warning signs?
• Given the pipe was assessed as having a 90-year expected life, is council investigating other similar pipes to ensure they are not at risk?
• Are RLC confident that any environmental risk factors from this leak are no longer an issue and what steps have been taken to ensure this is the case?

Response

From Stavros Michael, General Manager Infrastructure and Environment:

A damaged section of earthenware pipe carrying fully treated wastewater at the Rotorua Wastewater Treatment Plant has been replaced and is operating normally.

The pipe failure occurred on 19 November 2025. This type of failure is very rare. The affected pipe was the only one of its size and material at the site, and underground pipes like this are typically monitored operationally but physically assessed as they approach the later stages of their expected service life.

The pipe has now been fully CCTV inspected, with footage currently under review as part of an external specialist assessment. The possible causes of the failure are still being investigated so it’s too early to determine the cause or to evaluate the costs.

The damaged pipe has been sealed off and replaced with a temporary welded polyethylene pipe. A new permanent pipeline will be installed as part of the upgrade to the treatment plant that is underway.

Environmental testing following the leak confirmed that nearby lake water quality has returned to normal, with no ongoing bacterial contamination.