Moa Point Wastewater incident - Information hub
Tiaki Wai is responding to a significant incident at the Moa Point Wastewater Treatment Plant which has resulted in untreated wastewater discharging into the sea on the south coast of Wellington.
Wet weather may result in untreated wastewater discharging to Tarakena Bay and travelling around South Coast beaches. Check LAWA.org.nz before you go in the water.
The Recovery Road Map provides an indicative timeline and key milestones to restore the plant back to the way it was prior to the flooding, and address the design flaw identified in the hydraulic report.
Latest updates
Get the latest information:
Water sampling
Results of water sampling taken around the Moa Point Wastewater Treatment Plant short outfall pipe and southern coast beaches.
Odour
Managing and reducing odour is a top priority for us, every step of the way.
Public Health
-
Is it safe to swim?
LAWA ›The public should follow LAWA’s advice on whether beaches are suitable for swimming.
Water sampling has shown that overall, the water near the shore has been within the acceptable limits for safe swimming in dry weather conditions. 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 short such as surfing and diving should be conducted at people’s own risk.
Out of an abundance of caution, the recommended stand down period following the end of any discharges from the short outfall has increased from 48 to 72 hours. As we move into winter and are experiencing more frequent rain and strong southerlies, recent monitoring shows that water quality can take longer to return to acceptable levels. Heavy rain also increases urban runoff and stormwater discharges, which can affect water quality and is likely to be contributing to some of the high sampling results.
-
Is it safe to eat kaimoana?
Public Health advice ›No. People should not collect or eat kaimoana from the affected areas (Ōwhiro Bay to Breaker Bay) at this time.
Kaimoana can become contaminated by sewage. Shellfish such as mussels and pipi carry the highest risk because they filter large amounts of water and can concentrate harmful bugs, which may remain in their tissues for several weeks. Other species such as pāua, kina, crayfish, and fish are generally lower risk but can still be contaminated while sewage discharge is ongoing.
Because sewage discharge is continuing and conditions can change, the safest approach is to avoid collecting or eating any kaimoana from affected areas as a precaution to protect health.
-
Can I go on the beach and in the water?
LAWA.org.nz ›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.
-
Is it safe to swim in Wellington’s Harbour and other swimming spots such as Haitaitai and Oriental Bay?
LAWA.org.nz ›The best source of information for safe swimming areas is the LAWA website. Sampling does not suggest that wastewater from the short or long outfall is travelling around into the inner harbour.
-
Should I be concerned about wind and/or sea spray?
Public Health advice ›The risk of illness from inhaling contaminated sea spray is highest very close to where sewage is discharging, particularly when the short outfall is in use. The risk is considered very low elsewhere along the coast or further inland from the coast.
The biggest risk to health remains direct contact with contaminated water, such as swimming.
As a precaution during periods of high sea spray, people should limit the time they are exposed to sea spray close to where sewage is discharging when the short outfall is in use, keep windows closed, and wash and dry their hands after being outside.
-
What is the latest public health advice?
Public health advice ›All public health advice is available on National Public Health's website, here.
On 25 February, the public health advice on the beaches and water on Wellington’s south coast changed. People can now go on the beaches and swim near the shore in the area from Ōwhiro Bay to Breaker Bay. The public are strongly urged to check LAWA.org.nz before visiting beaches and entering the water, and follow LAWA’s advice. LAWA are Land, Air, Water Aotearoa. This excludes Tarakena Bay which remains a no-go area due to its proximity to the short outfall pipe.
-
I’ve been in the water recently at a South Coast beach and now feel unwell, what should I do and where do I go for advice?
Healthline ›If you have been exposed to the water and develop symptoms such as vomiting, diarrhoea, fever, cough, rash, irritation of the ears, nose or throat, seek medical attention and inform the healthcare provider of your possible contact with sewage. Healthline is a free over-the phone health service available 24 hours a day, 7 days a week on 0800 611 116.
What happened?
-
Who runs/owns the plant?
Since 1 July 2026, the plant has been owned and maintained by Tiaki Wai with operational support from Veolia.
Prior to this, Wellington City Council owned the plant and Wellington Water maintained it with operational support from Veolia.
-
Why didn’t we get into the plant overnight to start fixing it?
Essentially, it was not safe to do so. The plant was without power, and multiple floors and key areas of the plant were inundated with untreated wastewater. The main area, the size of an Olympic sized swimming pool, had wastewater up to three metres deep. This made it impossible to access the site without causing more issues.
-
What caused the incident at Moa Point?
Hydraulics report graphic ›As part of our emergency response, Wellington Water commissioned a hydraulic report on 5 February to help increase the flow of wastewater to the 1.8km long outfall pipe. This was a top priority, as it was vital to limit the discharge of untreated, unscreened wastewater to Tarakena Bay via the short outfall pipe.
The report developed a hydraulic model of:
-
-
the effluent pipelines, which carry wastewater out of the plant
-
the bypass system, which allows screened wastewater to bypass further treatment (e.g. disinfection) and be discharged out the long outfall pipe when the plant is at maximum capacity, and
-
the long outfall pipe.
-
This was commissioned to help us 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.
This is valuable information, but 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. We’ll continue to be fully transparent with the public, and all reports will be released as is appropriate.
The full report can be read here.
-
-
What areas are affected by the discharge of untreated wastewater?
https://www.lawa.org.nz/explore-data/wellington-region ›Tarakena Bay remains a ‘no-go’ area due to its proximity to the short outfall pipe.
Please check LAWA.org.nz and follow their advice before coming into contact with the water between Breaker Bay and Ōwhiro Bay. This includes Lyall Bay, Houghton Bay, Island Bay and Princess Bay.
-
What has happened at Moa Point?
Hydraulic report graphic ›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.
What's happening now?
-
Is there a risk of odour?
Odour updates ›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.
-
Is there anything the public can do to help?
Looking after your wastewater ›To help reduce blockages in the network, and the amount of debris discharged through the short outfall if it is used, only flush the 3 Ps.
That's pee, poo, and (toilet) paper.
During heavy rain, untreated wastewater may need to be discharged via the short outfall. Avoid flushing non‑biodegradable items such as wet wipes and sanitary products - this will stop these items from being discharged along the coastline.Wet wipes, fats and oils being sent down the toilet or drain can cause blockages in the network too, which can lead to wastewater overflows. Wipe your oily pots and pans out with a paper towel and chuck it in the bin.
-
Why is it going to take this long to fix the plant?
Moa Point updates ›The plant sustained serious damage, across a large area. More information on the damage can be found in the damage report, available on our website. We absolutely appreciate that every day the plant is offline makes a difference, so we’re working hard to bring the plant back into operation as quickly as possible. It’s important to be clear that this is an immense task. There are nearly 30 separate projects that form the full Moa Point recovery, taking place on a constrained site. Equipment needs to be manufactured and shipped. We’re taking every effort to move as quickly as possible, and as part of the recovery we have restarted and accelerated the major EIC project. This was already underway prior to the flooding, and we’ve had the benefit of having a lot of the equipment already in storage or being manufactured, shaving months off the recovery timeframe.
-
Is wastewater being screened?
The screens at the treatment plant are working. These screens remove items like sanitary pads and wet wipes from the wastewater, before it is discharged through the long outfall pipe. Wastewater that goes through the short outfall is not screened.
-
When will the plant be fixed by, and resume normal operations?
Get regular updates ›On 20 May, we released the Recovery Road Map. The road map provides an indicative timeline and key milestones to restore the plant back to the way it was prior to the flooding, and address the design flaw identified in the hydraulic report. We’ll report back on these key milestones regularly, so the community can hold us to account and keep track of our progress on the road to recovery. These dates are all indicative, and we’ll continue to do all we can to accelerate delivery.
You can view the road map here.
While all major repairs will be completed in November and full treatment processes will be up and running, minor repairs may take a few more months.
When primary and secondary treatment are started up, the quality of wastewater being discharged out to Cook Strait will be gradually improved. Primary treatment will remove heavy particles like faecal matter and sand from the wastewater, and secondary treatment includes a biological process which breaks down waste, and ultraviolet disinfection. From this point, it may take 6 to 8 weeks for the bacteria to fully stabilise and UV disinfection to be fully effective. We will monitor the quality of this treated wastewater and provide this information to the community.
We’ve prioritised the work to get the core treatment functions of the plant up and running first, so we can get fully treated wastewater flowing through the long outfall pipe as soon as possible. The plant will be fully restored back to pre-4 February 2026 operations in February 2027. At this stage, we expect to have completed work on remediating the hydraulic issue in the bypass in late 2027. This issue was originally identified in the hydraulic report released in March. We may also be continuing work on previously planned aeration system renewal work at this time.
-
Is the short outfall being used?
The short outfall is only being used in heavy rain, when the flow of wastewater to the plant is greater than the amount that can safely be pumped up to the plant and out the long outfall. As of 20 May, this has happened on four occasions. The chance of the short outfall being used will progressively decrease as recovery continues and the pumping capacity to the plant is increased.
Outside of the use of the short outfall in heavy rain, all wastewater is being screened and pumped through the long outfall, which is 1.8km long. Discharging wastewater out the long outfall into Cook Strait allows for greater dilution, and large inorganic solids like wet wipes and tampons are screened out.
The short outfall is the designed overflow point for the inlet pump station to the plant. It was originally built as the main outfall discharge location from 1899 to 1998, and was retained to discharge wastewater in emergency situations like an extreme weather event or mechanical failure to prevent untreated wastewater discharging back up the network where it would pose a greater risk to the community and environment. There is no existing consent for use of the short outfall.
The plant and the long outfall were commissioned at the same time, sending fully treated wastewater out the long outfall pipe. Prior to the plant and long outfall being built, all wastewater was discharged through the short outfall into Tarakena Bay with milliscreening treatment only.
What happens next?
-
Why is it going to take this long to fix the plant?
Moa Point updates ›The plant sustained serious damage, across a large area. More information on the damage can be found in the damage report, available on our website. We absolutely appreciate that every day the plant is offline makes a difference, so we’re working hard to bring the plant back into operation as quickly as possible. It’s important to be clear that this is an immense task. There are nearly 30 separate projects that form the full Moa Point recovery, taking place on a constrained site. Equipment needs to be manufactured and shipped. We’re taking every effort to move as quickly as possible, and as part of the recovery we have restarted and accelerated the major EIC project. This was already underway prior to the flooding, and we’ve had the benefit of having a lot of the equipment already in storage or being manufactured, shaving months off the recovery timeframe.
-
What happens now Tiaki Wai has taken over?
As of 1 July 2026, as per legislation, Wellington Water amalgamated with a new water entity, Tiaki Wai. Tiaki Wai is the new organisation that will deliver drinking water, wastewater and reticulated stormwater services across the metropolitan Wellington area from 1 July 2026. The recovery programme continues as set out in our Road to Recovery map.
-
What are you doing to stop this from happening again?
There are two parts to the solution. To prevent a future flooding event, we are installing controls to automatically lock the inlet pumps (which control the flow of wastewater into the plant) if there is a risk of flooding detected in the UV outlet. We are also addressing the issue revealed by the hydraulic report. 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 the wastewater backwards and flooding the plant. This risk is being actively and carefully managed until the bypass project is complete by limiting the amount of flow pumped to the plant. At this stage, we expect work on the bypass to be completed by late 2027.
Environmental and recreational monitoring
-
Is it safe to swim?
LAWA ›The public should follow LAWA’s advice on whether beaches are suitable for swimming.
Water sampling has shown that overall, the water near the shore has been within the acceptable limits for safe swimming in dry weather conditions. 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 short such as surfing and diving should be conducted at people’s own risk.
Out of an abundance of caution, the recommended stand down period following the end of any discharges from the short outfall has increased from 48 to 72 hours. As we move into winter and are experiencing more frequent rain and strong southerlies, recent monitoring shows that water quality can take longer to return to acceptable levels. Heavy rain also increases urban runoff and stormwater discharges, which can affect water quality and is likely to be contributing to some of the high sampling results.
-
Who is responsible for cleaning up the beaches?
Only contractors from Wellington Water and Wellington City Council with the relevant health and safety clearance are undertaking this work.
-
Is it safe to swim in Wellington’s Harbour and other swimming spots such as Haitaitai and Oriental Bay?
LAWA.org.nz ›The best source of information for safe swimming areas is the LAWA website. Sampling does not suggest that wastewater from the short or long outfall is travelling around into the inner harbour.
-
I am concerned about the potential environmental impacts of this discharge. Where should I go for official advice?
Greater Wellington Regional Council ›Queries about environmental impacts should be directed to Greater Wellington Regional Council.
We are undertaking daily water sampling, the results of which are being published on our website daily.
When the short outfall is used, the shoreline is inspected and any debris is cleaned up.
-
Where can I access the latest water sampling results?
Sampling results ›We publish sampling results here each day.