What is Nature Calls?
Nature Calls is Palmerston North’s long-term project to upgrade how we treat and discharge the city’s wastewater over the next 35 years.
Every time you empty a sink, flush a toilet, run your dishwasher or use your washing machine, that water eventually makes its way to our wastewater treatment plant at Tōtara Road. There, it’s treated before being discharged into the Manawatū River.
In September 2026, Council confirmed how we will treat and discharge wastewater for the next 35 years
The decision was our Tōtara Road wastewater treatment plant will get a significant upgrade, so wastewater is treated to a much higher standard before being discharged to the Manawatū River at or near the existing outlet.
The treatment plant upgrade is estimated to cost $340 million and will:
- remove significantly more nitrogen and phosphorus
- achieve extremely low bacteria levels
- exceed new national standards for all other requirements
Alongside the treatment plant upgrade, about $40 million over the next 35 years is planned for adaptive management. This will allow further improvements to be made as technology develops, environmental expectations change and new opportunities become available.
Our current wastewater discharge consent expires in 2028
Nature Calls came to life about because we need a new long-term consent for how the city treats and discharges its wastewater.
While our existing treatment plant consistently meets the conditions of our current resource consent, the upgrade will significantly improve the quality of the treated wastewater discharged into the river. It will also meet the demands of our growing city, changing environmental expectations and new national wastewater standards introduced by the government.
Nature Calls began in 2017 to identify a long-term solution
After several years of technical and cultural assessments and community consultation, Council selected a solution in 2021 that involved discharging highly treated wastewater to both land and the Manawatū River. A resource consent application based on this approach was lodged with Horizons Regional Council in 2022.
By 2024, the estimated cost of delivering that proposal had increased to more than $640 million. During consultation on our 2024–34 Long Term Plan, our community told us that level of investment was unaffordable.
Council responded by setting a project budget of $480 million, plus inflation, and asking staff to investigate what could be delivered within that amount.
The introduction of national Wastewater Environmental Performance Standards in December 2025 also changed the requirements the project needed to meet and helped narrow the solutions available.
In April and May 2026, we asked the community for feedback on two river discharge approaches that could meet the new standards within the revised budget.
Following that work and community feedback, Council confirmed the Tōtara Road approach in September 2026.
You can find the reports, consultation material and technical information that informed these decisions in our Nature Calls library.
Adaptive management allows us to keep improving over time
The treatment plant upgrade is the major investment we need to make now, but we also know wastewater technology and environmental expectations will continue to change over the next 35 years.
That’s why adaptive management is an important part of Nature Calls.
Rather than locking every aspect of wastewater management into one solution today, about $1 million a year is planned for further improvements over the 35-year life of the new consent.
These could include further treatment improvements, new technology, diverting wastewater from the river at times, wastewater reuse, riparian planting and initiatives to recover useful resources from wastewater.
The adaptive management programme will be developed further as the project progresses.
We’ve worked closely with iwi
Iwi have provided cultural advice and feedback throughout Nature Calls, alongside the technical, environmental and community feedback and evidence that has shaped the project.
That partnership will continue to be important as the project moves into delivery and the adaptive management framework, which will be developed alongside Rangitāne, Ngati Whakatere and Te Tumatakahuki.
Delivery of Nature Calls will transfer to Central Districts Water
Council’s decision gives Nature Calls a clear direction as work continues towards securing the long-term consents needed for the city’s wastewater treatment and discharge.
We’ll continue progressing Nature Calls until responsibility for the city’s water services transfers to Central Districts Water on 1 July 2027.
Central Districts Water will then be responsible for funding and delivering drinking water, wastewater and stormwater services across Palmerston North, Horowhenua and Rangitīkei, including taking Nature Calls forward.