Pahiatua Water Treatment Plant

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Project Overview

Progress and Updates

Photo Gallery

Frequently Asked Questions (FAQ)


Project Overview

The Pahiatua Water Treatment Plant is a totally new plant that will take water from the existing Pahiatua bore and the Mangatainoka River and treat it to produce water that is better than NZ Drinking Water Standards. It does this with Ultra Fine (UF) membranes and advanced oxidising ultraviolet (UV) technology that can remove impurities and deal to taste and odour issues that are present in the water.


Why are we doing this?

This project aims to deliver quality water to the Pahiatua community and visitors. Quality water is water that meets NZ Drinking Water Standards and that manages taste, odour and discolouration.


What are we doing?

  • Treating turbidity and improving security of supply: The new plant will be able to treat the high levels of turbidity (cloudiness or haziness) in the water from the river. Previously, the water take from the river has been cut off during periods of very high turbidity and Council has had to rely on the supply in the Pahiatua bore. The new plant, coupled with the new 6,000 cubic metre reservoir, will provide Pahiatua with a reliable source of drinking-water well into the future.
  • Making considered and future-proof decisions: The plant is located next to the existing water treatment plant and adjacent from the wastewater treatment plant. It has been designed to limit the noise produced by the plant and minimise noise for any neighbouring properties. The plant has allowed space for future developments with room for more UF membranes should the population grow (therefore increasing demand).
  • Utilising technology: The plant has been designed so that it can be operated remotely and only requires staff to visit for scheduled maintenance or to received a delivery of chemicals for chlorination and cleaning will every 4-6 weeks.


Progress and Updates

Current progress

Click on the image below to view the project progress map for the Pahiatua Water Treatment Plant.

Pahiatua WTP.png (33KB png)

Latest project updates

20 July 2020:  New water treatment plant set to deliver soon

Pahiatua’s new state-of-the-art water treatment plant, to ensure public health, is on track to be commissioned in September.

The new plant, which will remove taste and odour issues from the bore and river water, is looking very, very impressive and will be a big win for Pahiatua, Tina Love, the Performance Manager for the project, said.

“In the last month we’ve completed the civil site work, with the site construction finished in early August,” she said. “We have started factory acceptance of the control and systems technology, with all work completed by the end of September.”

Filtec and Morris and Bailey worked hard to keep the project moving during the Covid lockdown levels, minimising delays.

“There were no major delays, with really good progress made. It was brilliant,” Tina said.

Along with the state-of-the-art treatment plant, the site also boasts a New Zealand first.

“Onsite we have chlorine trolley on an automated, motorised rail system, the first of it’s kind in New Zealand,” Tina said.

The motorised chlorine trolley is an innovative idea from Filtec that removes the requirement for operators to manually push in excess of 1 ton drum and trolley along a track during changeover. With safety in mind, the motorised chlorine trolley has been designed to move in and out of the chlorine room using push button controls and has a number of safety features built in to ensure it does not operate outside of its intended parameters.

Filtec Alliance Manager Stephen Lee said the mechanical and electronic teams have been busy installing and connecting all the services and hooking up equipment, with this work in its final stages.“The next step will be flushing the lines, in preparation for commissioning work which is starting in August,” he said. “We plan to have the plant producing water by the end of September after a complicated start-up of all the equipment, making sure it runs automatically.”

Testing and fine-tuning for the right chemicals will also take place.

The plant has been designed to be operated remotely, only requiring staff to visit for scheduled maintenance or to receive delivery of chemicals for chlorination. Cleaning will take place every four to six weeks.

“We had a challenging time through the design and planning of this project, but after all those challenges and changes we’re pleased to have seen good progress,” Stephen said.


    14 May 2020: The building structure is complete, the roof is on and all external concrete has been laid.

17 February 2020: Walls have been erected on site, building is starting to take shape

15 January 2020: Workers are back on site, and have nearly completed drainage. The panels are being built offsite concurrently to drainage works.

16 December 2019: Modifications have been made to the initial design prior to building consent being issued, and a focus is on completing ducting, drainage and foundation work. 

26 September 2019: The Iwi blessing of the water treatment plant site and build process has taken place, with ground works commencing with civil contractors Morris & Bailey working on site.

The resource consent has also been granted, and finalisation and peer review of the last design elements is underway. The building is going through some final design changes, in preparation for the build work to commence.

2 September: As at the beginning of September, the Detailed Design of the Plant has been substantially completed and construction can now start. See full project update... (290KB pdf)


Photo Gallery


Frequently Asked Questions (FAQ)

Why is a new water treatment plant required?

Pahiatua’s water supply is drawn from two sources – the Pahiatua bore and the Mangatainoka River. Following a decline in volume of Pahiatua’s bore and with ongoing issues arising from the river water supply (i.e. taste, odour and discolouration), the search for a water source to supplement supply has been ongoing and unfortunately, not successful. Several sites were assessed but no satisfactory source has been found for the volume required.

Continued use of the Mangatainoka River as the additional source is currently the only option with certainty for available volume.

Have neighbouring properties been considered?

The new Water Treatment Plant, which is proposed to be located adjacent to existing water and wastewater treatment plants, will be purpose built to reduce noise impacts on neighbours.

Council hosted an on-site session in April 2019 for neighbours to ask questions of Council staff, and get further information.

What is Council doing to future-proof this new asset?

The Water Treatment Plant will be built to “Importance Level 3 of the Building Code”, ensuring that the Plant is designed for a greater level of earthquake shaking than ordinary commercial structures.

Additionally, the Plant will be future-proofed with room for more filters should they become necessary for population or demand growth (and as new technology becomes available).

Will there be impacts on street traffic?

Residents on the north side of Hamilton Street will experience increased traffic along the Council access way at the back of their properties during the construction of the Plant. This is unavoidable during the construction phase.

Once construction is complete, this will return to normal (if not reduced) levels of traffic. Chemical deliveries to the Plant will occur less often with a larger truck coming every 6 weeks or so (in comparison to the current situation of smaller, more frequent deliveries).



If you have a concern, complaint or compliment regarding this project, you can speak with a member of the Project Team by calling 06 374 4080 or 06 376 0110. You can also email with your contact details and request for a member of the Project Team to get in touch with you.