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Projects / Te Mārua Water Treatment Plant Capacity Upgrade

Te Mārua Water Treatment Plant Capacity Upgrade

Current status
All Updates

On behalf of Greater Wellington Regional Council, we are upgrading the Te Mārua water treatment plant to ensure reliable and healthy drinking water for the residents of the Greater Wellington Region.

Start Date
End Date

If you have any questions about this work, please contact:

Wellington Water, 04 912 4400

Latest Updates

20 October 2023

Since our last update in August, we’ve made great progress on site – and you can check it out in our new time-lapse

16 August 2023

Construction is now well underway.

27 April 2023

Major enabling works kick off

Initial enabling works commenced in February 2023 and will be followed by component upgrades.


Why are we doing this work?

The Te Mārua water treatment plant is a critical infrastructure asset to Wellington region. It currently provides up to 80 million litres of drinking water per day (MLD), at an average of 60 MLD - approximately 45% of the Wellington region’s 135 MLD drinking water demand.

The plant is designed for a maximum plant flow of 140 MLD, however is currently limited to 80MLD under specific raw (untreated) water conditions. 

Recent population growth forecasts and water consumption data indicate that over the next two years the risk of water supply restrictions to customers could increase significantly.

We are optimising the treatment capacity of the Te Mārua plant to achieve the 140 MLD target of safe drinking water under projected, future raw water conditions.

These upgrades will allow the plant to provide a larger amount of water to meet the needs of the region, while also improving the plant’s ability to remove algae, sediment, and odour from the water.

What does the upgrade involve?

A key part of the capacity upgrade is installing a Dissolved Air Flotation (DAF) plant. This technology involves using air bubble flotation to remove suspended solids, oils, and other contaminants from raw water. The DAF is manufactured by Canadian company AWC Process Solutions, a word-leader in these systems.

Enabling works for the project kick off in February 2023 followed by a range of initial component upgrades including a new lime silo and CO2 tank.

Installing the DAF plant is expected to start late 2023 or early 2024 with the goal of commissioning the plant in October 2024.

The upgrades will be planned and executed without compromising drinking water supply and quality from the plant.

All Updates

20 October 2023
  • We’ve installed and commissioned the replacement CO2 dosing system and bulk storage tank, this system is now in service.
  • The lime silo has been installed on its foundations and will be commissioned later this year.
  • Following the completion of service relocations, the excavation for the new Dissolved Air Flotation (DAF) building are nearly complete. The DAF is the primary focus of the project, and when combined with the other system upgrades onsite, will increase the water treatment plant’s capacity by up to 60 ML/d.

These upgrades will increase the treatment capacity of the plant to meet the growing needs of the region, while also improving the plant’s ability to remove algae, sediment, and odour from the water.

 We look forward to providing another update soon on this exciting project.

16 August 2023

Good progress is being made on the new lime silo and the new CO2 dosing system storage tank.

 Later this year, we’re set to start constructing the foundations for a new dissolved air floatation (DAF) unit to increase the output capacity.

27 April 2023

Major enabling works are now underway for the Te Mārua water treatment plant upgrade.

Since February, the focus has been on completing initial works.

Today, we kicked off works to enable major component upgrades with piling for the pad that will eventually hold the new carbon dioxide storage tank.

The piling works will continue for the next week . Then we’ll be ready to commence the piling for the lime silo pad.