The public should follow LAWA’s advice on whether beaches are suitable for swimming. 

Daily sampling along the coast has shown that during dry weather (excluding the days immediately following wet weather) these results have been within the acceptable bacterial levels for safe swimming near the shore.

Some caution is still advised. The sample sites have not included areas out in the Cook Strait near the long outfall pipe, so activities further from the shore such as surfing and diving should be conducted at people’s own risk. 

 Following the flooding on 4 February, the Moa Point Wastewater Treatment Plant is not fully operational.  

The plant suffered extensive damage when it was flooded with wastewater. It lost power, and untreated, unscreened wastewater was discharged to Tarakena Bay, on Wellington’s south coast. 

  A hydraulic report was commissioned the day after the incident to help Wellington Water understand: 

• how the bypass system could be operated during the recovery phase, and  
• the hydraulic constraints on the system once the plant’s treatment process is brought back online, while the UV upgrades are underway. 
 
While this hydraulic report was not commissioned to identify the cause, it has revealed some valuable information, which helps us to understand what appears to be a significant factor at the plant during the flooding event.  
 
The report found that air can become trapped in the wastewater bypass pipeline, particularly when there is a high flow of wastewater passing through the plant. It is possible that trapped air could disrupt the flow of wastewater, pushing it backwards and flooding the plant. 

While this is valuable information, these findings are just one piece of the puzzle. There are other areas of interest that require a more detailed investigation, and Wellington Water has commissioned an external specialist to conduct a wider investigation into these other factors.

A graphic has been created to help explain the hydraulic issue. The full report can be read here.

While we continue our work to recover the plant, we are investigating opportunities to resume or accelerate delivery of projects that were underway or in the planning stages when the flooding occurred.

Currently, two existing renewal projects that were impacted by the flooding can resume. The designs for these projects had already been completed, and some of the equipment was either in storage or already being manufactured. As a result, we have not needed to start from scratch – and aren’t facing the usual risks of long lead times and shipping delays. Here’s some more information on those projects: 

Electrical, Instrumentation and Controls (EIC) renewals  

A priority at the Moa Point Wastewater Treatment Plant was to renew and upgrade the SCADA (Supervisory Control and Data Acquisition), PLC (Programmable Logic Controller) and MCC (Motor Control Centre) systems - essentially the brain, heart and nervous system of the treatment plant.  Without these systems, the plant would be unable to function.

This project began a couple of years ago and was already in the construction phase when the flooding occurred. Key components were being fabricated offsite, and we are now accelerating their manufacturing and installation as a crucial foundation for our recovery. Currently, the team are finishing up the removal of damaged electrical equipment and componentry in the switchroom. Some core components are in the process of being manufactured offsite, including the Motor Control Centres.

UV project

We’re pleased to confirm that work on the UV system has restarted. This follows strong progress on ventilation improvements in the plant’s UV room, which were essential to ensure worker safety.

Ultraviolet (UV) is used to disinfect wastewater, and is the final stage of treatment before it is discharged. The existing UV system was at the end of its life and no longer able to reliably meet the required level of treatment performance. Work to replace the UV system was already underway, and was disrupted by the flooding. Much of the equipment had been ordered and stored offsite, which has enabled the team to restart the project quickly.

While having the equipment on hand has been an advantage, high hydrogen sulphide levels in the UV room created a significant safety risk and needed to be resolved before work could resume. Ventilation work is now complete, allowing the UV project to restart.

Recovery programme

We are continuing work to plan the recovery programme as quickly as possible. The recovery programme is an overarching programme of works, which captures the broad timelines of the steps we’ll take on the road to recovery.  

There are multiple projects and workstreams being planned underneath the overarching programme, many of which depend on one another or may be influenced by external factors like manufacturing or shipping timeframes. These dependencies and interdependencies mean the plan is complex and must be developed carefully to manage risks and sequencing effectively.

This robust process will help us make sure the road to recovery is smooth and we achieve the right outcomes for Wellingtonians. While we cannot provide a specific timeframe for the programme to be finalised, we will release it to the public as soon as is appropriate.

For regular updates, check here.

As you may know, Moa Point’s odour treatment systems are not working following the flooding on February 4th. This means that it is likely that odour from the plant will be noticed by the community. This is an ongoing risk, until odour treatment is restored at the plant.

Restoring odour treatment at the plant is a top priority for Wellington Water, and we are working on a solution as quickly as we can. However, it will not be a quick fix – and it’s important that we continue to be upfront with the community on the likelihood that odour will be experienced intermittently for the coming months.

Reducing odour remains a top priority. The plant’s odour‑control systems were damaged in the flooding, and removing sludge and screened material may cause temporary odour increases.

One of our first priorities was to clear the plant of sludge. When the plant stopped operating, the wastewater treatment process also stopped. This left wastewater inside the plant at various stages of treatment, including sludge (wastewater solids). It is important for us to remove this sludge as soon as possible before it became septic, which could cause significant odour and a health and safety risk to workers onsite.

Odour neutralisers and monitors are being installed, and odour scouts are regularly assessing conditions both inside the plant and in surrounding areas. Restoring odour‑control systems is underway.

To make a complaint about odou, please contact Greater Wellington Regional Council on 0800 496 734.

Recovery programme

We are continuing work to plan the recovery programme as quickly as possible. The recovery programme is an overarching programme of works, which captures the broad timelines of the steps we’ll take on the road to recovery.  

There are multiple projects and workstreams being planned underneath the overarching programme, many of which depend on one another or may be influenced by external factors like manufacturing or shipping timeframes. These dependencies and interdependencies mean the plan is complex and must be developed carefully to manage risks and sequencing effectively.

This robust process will help us make sure the road to recovery is smooth and we achieve the right outcomes for Wellingtonians. While we cannot provide a specific timeframe for the programme to be finalised, we will release it to the public as soon as is appropriate.

For regular updates, check here.

Some advice is available on the Greater Wellington Regional Council website.

We are undertaking daily water sampling, the results of which are being  published  on our website weekly.

When the short outfall is used, the shoreline is inspected and any debris is cleaned up.  

We publish sampling results here each week on our website.

We shifted from publishing sampling data daily, to publishing it weekly. This is because daily sampling along the south coast has shown that since the long outfall began discharging untreated wastewater out to Cook Strait, during dry weather (excluding the days immediately following wet weather) these results have been within the acceptable bacterial levels for safe swimming near the shore.

Some caution is still advised. The sample sites have not included areas out in the Cook Strait near the long outfall pipe, so activities further from the shore such as surfing and diving should be conducted at people’s own risk.    have done water sampling around the South Coast. These tests take at least 24 hours to produce a result as the bacteria has to be grown in the lab.