New southern wastewater plant for Hamilton endorsed by key commission

Monday, 30 June 2025

Hamilton’s Pukete Wastewater Treatment Plant - a southern city equivalent is expected to cost more than $500 million over time.

A new $500 million-plus wastewater treatment plant south of Hamilton has made it onto a national priority list, raising the mayor’s hopes that it could be developed faster.

The Southern Metro Wastewater Treatment Plant would be southwest of Hamilton and serve both the city and Waipā.

It’s one of 17 projects around the country that are “positively endorsed” by the independent Infrastructure Commission in a draft National Infrastructure Plan.

Hamilton mayor Paula Southgate says this raises her hopes of getting quicker action on construction.

The proposed plant would be about equivalent to the existing one at Pukete and would help ease wastewater capacity constraints that are currently stifling housing developments in large parts of the city.

Hamilton mayor Paula Southgate said inclusion on the list “absolutely” made her more optimistic about getting Government support for faster action. The plant currently has no construction funding set aside by the city or Waipā in their 10-year plans.

Infrastructure Minister Chris Bishop says “improving the way we plan, fund, maintain and build our infrastructure is critical to boosting economic growth”.

The wastewater plant is assessed in the draft plan as being at “stage 1”, meaning the proposal “identifies a nationally important problem or opportunity that may have a feasible solution”.

“Ongoing population growth and development in the [Hamilton] metro area and the broader Waikato River catchment is increasing pressure on land and water. This proposal is looking to address these issues,” the draft plan said.

Infrastructure Minister Chris Bishop has said the list is modelled on an Australian one which had helped build political consensus across the Tasman on a pipeline of major projects.

If your property is in one of the blue areas on this map of Hamilton, you are living in a ‘constrained wastewater zone’.

“Proposals that pass the test will be identified as priorities for New Zealand. This does not guarantee funding – but it does provide decision makers with a menu of credible proposals which could inform investment decisions.”

While the plant wasn’t one of three projects described as “investment ready”, Southgate said making the list gave her more confidence the Government could be more focused on helping facilitate its development.

“We’ve always believed that the best thing for north Waipā and south Hamilton would be to have another [plant] at the right time because of the scale and efficiency that one water plant would deliver for all of the new development that’s coming in that part of the city. It also frees up capacity in the north.”

Inclusion on the commission’s list implied the project had merit.

“It supports the view that it is a good investment…and so now we need to talk to all the parties, and all people who would benefit from that wastewater plant, to see how we go forward. That’s unclear at the moment.”

The Eastern Transport Corridor would beef up the various transport links to the Ruakura Superhub.

But a wastewater system that future proofs and enables growth, and was cost effective, was “definitely the right solution for one of the fastest growing areas of New Zealand”.

She pointed out that several residential projects had been given fast-track approvals in the area and may benefit from a new plant.

“So the big question to look at now is whether we can partner with developers to get that work done or whether we’re going to see numerous small wastewater plants or systems, as is allowed for.” She said going with the latter could affect a new plant’s cost-benefit ratio.

Land for the plant had been bought in the southwest of the city near the airport and the city council had been funding investigation and design work. But no funding had yet been allocated by the city and Waipā councils for construction, Southgate said.

A second Waikato project on the list is the more advanced Ruakura Eastern Transport Corridor (ETC), a proposed $300 million four-lane project.

Earlier this month, Bishop announced the NZ Transport Agency had endorsed the business case for the ETC, signing off $4.1 million to complete consenting and detailed design.

Once complete the four-lane corridor would enable the completion of the Ruakura inland port while also unlocking residential and commercial land for the superhub.

The ETC would run from the superhub to the southern end of Fairview Downs, connecting to the Fifth Avenue extension.

The $4.1 million cost of the pre-implementation phase will be shared with the city council, with the transport agency contributing just under $2.1 million.

Implementing the ETC is currently timed for 2027-30, subject to further funding being approved.