Owners of Lake Tarawera properties being connected to a council sewerage network will not learn the total amount it will cost them until the middle of this year.

Rotorua Lakes councillors received an update on the Tarawera Sewerage Scheme during an Infrastructure and Environment Committee meeting on Wednesday.

The multi-million-dollar scheme would see one of the last of the district's communities connected to sewerage reticulation, but its ratepayers are concerned about what it will cost them.

Council infrastructure and environment deputy chief executive Stavros Michael acknowledged the cost to the community and the 'legitimate” concerns around this, and said the council would work to explore additional funding support.

The cost of the project was 'significantly higher” than was expected in 2018, he said.

Late last year, the council estimated the project's total gross cost would be $23 million to $32m.

Michael said the project had been split into two stages to safeguard a $6.5m subsidy from the Ministry for the Environment. Rotorua Lakes Council and Bay of Plenty Regional Council jointly contributed about $1.5m, for a total of $8m in subsidies.

The cost of both stages of the project would be divided between about 550 properties, including roughly 100 new properties, to be connected to the scheme.

Excluding subsidies, the average net cost to each property would be about $12,500 for stage one, but stage two costs were yet to be settled, Michael said.

Costs are now 'significantly higher” than was expected in 2018, Rotorua Lakes Council infrastructure and environment deputy chief executive Stavros Michael said. Photo: Laura Smith/Local Democracy Reporting.

The council has allowed up to $15m, including a contingency of $1.34m, for the construction of stage one.

This stage involved laying 24 kilometres of pipes and installing five pump stations in the area, which would provide for the connections.

Stage two would see the roughly 450 existing properties connected to that network, with another 44km of pipes.

On Wednesday, councillors were asked to consider procurement plan options for stage two.

They voted to approve a public open tender for the full scope of work, including the supply and installation of low-pressure grinding pumps as well as pipes, valves and boundary assemblies.

This option had been recommended as the most competitive and transparent.

Councillors Robert Lee, Lani Kereopa and Don Paterson voted against it.

Lee said he attended a community meeting about the scheme the day before the council meeting and said concern focused on the cost.

He asked how many from the community expressed support for the reticulation system, and Michael said 95 per cent.

Councillor Robert Lee asked how homeowners could consent without knowing the costs of stage 2 of the project. Photo: Laura Smith/Local Democracy Reporting.

Lee asked how residents would have been able to give informed consent to the project when they did not know how much it would cost them.

Michael said residents were advised of the cost of stage one and a comprehensive costing for stage two was under way.

Costs for the overall project would not be known until the end of June or early July when the stage two tender process was complete.

Michael said there had been conversations with the community since 2017 on the scheme and a reference group was established to work with the council and on the options.

Michael said there was a strong and frank relationship with the community.

In 2020, the council agreed to the present project and estimated the cost per household would be $30,300.

Councillor Conan O'Brien asked that when costs were known, they should be looked at with compassion to the residents, and the council should look for long-term solutions.

'I feel the price is not going to come down. The sooner we get on and get this completed, [it] will be better for everyone in that community and Rotorua, and the lakes.”

Councillor Rawiri Waru said in his view, no one was 'keen on paying more”, but residents knew it needed to be done.

'Septic tanks are not acceptable any more, and they are illegal. We have to do something out there. The cost will always be an issue.”

Rotorua deputy mayor Sandra Kai Fong said costs had already risen because of delays and it could not afford to wait any further.

'There are cost implications to the community as a whole if we do not protect the environmental status of the lake water quality.”

She said the effect on the 170 properties using the now-illegal septic tanks meant there would be an 'even bigger financial burden” on them if they were to be red-stickered.

Local Democracy Reporting is Public Interest Journalism funded through NZ On Air