What’s the story: Christchurch Wastewater Treatment Plant smell
We know many communities across Ōtautahi Christchurch have been affected by the persistent stench from the fire-damaged Christchurch Wastewater Treatment Plant in Bromley. For many residents, over several years, this has had a significant impact on daily life and wellbeing.
As the environmental regulator, Canterbury Regional Council (Environment Canterbury) takes these impacts seriously. Following thousands of reports from residents about the strong, sewage-like smell affecting east and central suburbs, we issued an abatement notice to Christchurch City Council (CCC) on 26 February 2026.
This notice required CCC to demonstrate how it was addressing the odour issues at the wastewater treatment plant.
Independent assessment confirms compliance with abatement notice
CCC submitted its response to the abatement notice on Tuesday 16 March 2026. Since then, Environment Canterbury compliance staff have worked with an independent wastewater engineering expert to rigorously assess the information provided, and determine whether it met the requirements of the abatement notice.
We have now received the independent assessment, which confirms that CCC has met all conditions of the abatement notice and has taken meaningful action to reduce odour.
This includes the decision to install additional aerators in the treatment ponds. The independent expert concludes this is the most effective mitigation option available to reduce odour risk while construction of the new activated sludge reactor continues. No further immediate mitigation measures were recommended.
Based on this assessment, We have determined that the legal requirements of the abatement notice have been met. On Tuesday 5 May, we formally advised CCC of this decision, shared the key findings from the independent report and cancelled the abatement notice.
What happens next
While the abatement notice has been lifted, this does not mean the issue is resolved. The wastewater treatment system remains vulnerable during the fragile seasonal transition period, and the effects of the stench are still being felt by the community.
We will proactively follow up with CCC on the recommendations in the report, requesting further detail and timeframes for CCC’s commitments in response to the abatement notice.
We will continue active compliance monitoring of CCC’s operation of the fire‑damaged plant as it progresses delivery of longer‑term solutions. CCC will be held accountable for delivering its agreed actions, and further enforcement action will be taken if required.
📢 Stay updated: We’ll continue to share updates with the community via this webpage and on social media as new information becomes available.
Updates
17 March 2026
Action plan received
Christchurch City Council submitted its response to the abatement notice issued by Environment Canterbury on Tuesday 16 March. The notice, issued on 27 February, requires an action plan setting out short and long-term measures to reduce the stench coming from the Christchurch Wastewater Treatment Plant in Bromley.
The notice follows more than 5,500 community reports describing a strong sewage-like smell affecting residents across East and Central Ōtautahi Christchurch since late January 2026.
Our compliance team is now working urgently with our wastewater specialist to assess the plan and ensure it meets the expectations set out in the abatement notice. This assessment may take some time to complete.
If the plan is not satisfactory, further enforcement action may be taken.
5 March, 12pm
Next steps after abatement notice issued for treatment plant stench
On Monday 2 March, Christchurch City Council announced it is investigating whether a portion of the wastewater from the Christchurch Wastewater Treatment Plant could be diverted to the ocean outfall pipe as a potential interim solution to help reduce the ongoing stench.
Yesterday, Wednesday 4 March, our staff met with Christchurch City Council to learn more about this proposal to discharge partially treated wastewater to sea via the existing outfall pipe. A detailed plan has not yet been developed by City Council staff.
As expected, there is considerable work required to develop the concept into something that can be assessed and implemented.
We will continue to work closely with and support Christchurch City Council – in partnership with mana whenua – to ensure they prepare a fully developed proposal that is satisfactory to all parties and the meets requirements for a resource consent.
We are very pleased to see this work now progressing at pace to deliver a solution for affected communities and look forward to seeing more detail as it becomes available.
Christchurch City Council has until 16 March 2026 to supply a plan outlining both short- and long term odour-mitigation measures, along with achievable timeframes.
We will continue to support CCC and the National Public Health Service to ensure this issue is resolved for our impacted communities.
27 February, 12 pm
Abatement notice issued for treatment plant stench
On 26 February 2026, Environment Canterbury issued Christchurch City Council an abatement notice for failing to provide an adequate action plan to address the persistent stench coming from the fire-damaged Christchurch Wastewater Treatment Plant in Bromley.
Environment Canterbury previously signalled to Christchurch City Council that delays in taking effective and timely action could result in the use of statutory tools.
Issuing this abatement notice today demonstrates that we are serious about establishing a clear path toward long-term, sustainable solutions for the plant that bring relief to affected communities.
Christchurch City Council has until 16 March 2026 to supply a plan outlining both short- and long term odour-mitigation measures, along with achievable timeframes.
We will continue to support CCC and the National Public Health Service to ensure this issue is resolved for our impacted communities.
29 January, 9 am
The facts - what’s happening right now
Our team is working closely with Christchurch City Council (CCC) to resolve the current problem operationally at the treatment plant and get a solution in place.
- CCC has advised us that heavy rainfall this month has significantly affected the health of several oxidation ponds.
- Monitoring on 26 January showed a drop in dissolved oxygen (DO) levels across the system. Low oxygen conditions make smells far more likely, particularly in Ponds one, two, and three, which are currently the most affected.
- The ponds are also under extra pressure from higher than usual loading and patches of sludge rising to the surface, further increasing the chance of smells escaping into nearby communities.
Christchurch Wastewater Treatment Plant operations teams are closely monitoring conditions and responding wherever possible to improve pond health and minimise smell. This includes:
- Adjusting flows through the ponds to stabilise loading.
- Regular monitoring so we can react quickly to changes.
- Using all available operational tools to support oxygen levels and improve pond performance.
What we are doing
Our first priority is to ensure the smells are controlled as fast as possible. We have issued a formal request for CCC to provide confirmation of the actions they are taking and timeframes to rectify the current situation and address the smells.
This will also include a requirement for CCC to set out the proactive actions they will take to mitigate the potential for any future smell issues.
We are also actively considering what, if any, punitive enforcement action may be appropriate and in the public interest.
At present, CCC are working closely with us to address the issue. However, any delays in taking effective and timely action will likely result in the use of statutory notices to compel action.
As the plant is a critical piece of public infrastructure, our current enforcement approach is to work with CCC on improving smell as soon as possible. This approach doesn’t lessen our commitment to expecting compliance, and the issue continues to be under investigation.
Managing and monitoring discharges to air in our region, including smells, is part of our responsibilities as a regulator under the Resource Management Act (RMA) and the Canterbury Air Regional Plan.
What happens next
We will continue to work closely with CCC to ensure they are meeting their consent conditions and putting smell mitigation measures in place wherever practicable.
Report a smell
Your reports are an essential part of this work. They help us understand what you’re experiencing in real-time and guide the timing and location of our monitoring.
If you notice strong, unusual, or unpleasant smells, please continue to report it through the Smelt It app, or on 0800 765 588 (24 hours)
Advice from the National Public Health Service
Feeling unwell from the smell? We have checked in with Health NZ Te Whatu Ora and here's their advice from Dr Annabel Begg, Medical Officer of Health for the National Public Health Service:
- Exposure to hydrogen sulfide odour arising from the Christchurch wastewater treatment plant can cause nausea, headaches, eye and throat irritation, skin irritation, sleep disturbance, and worsening asthma symptoms at relatively low concentrations.
- If people exposed to the odour don't experience physical health effects, continued exposure to unpleasant or nasty, noxious odours can still have an adverse effect on people's mental wellbeing.
- While exposure to hydrogen sulphide is unpleasant and may result in health effects, it doesn’t accumulate in the body. Any health effects would be expected to resolve when the odours are brought back to normal levels, and long-term health effects are highly unlikely.
- People experiencing health issues as a result of the smells coming from the treatment plant should seek health advice from their GP, doctor, Hauora or healthcare provider, or call Healthline free on 0800 611 116, anytime 24/7 for advice as soon as possible. In an emergency call 111.
Christchurch Wastewater Treatment Plant operations teams are closely monitoring conditions and responding wherever possible to improve pond health and minimise smell. This includes:
- Adjusting flows through the ponds to stabilise loading.
- Regular monitoring so we can react quickly to changes.
- Using all available operational tools to support oxygen levels and improve pond performance.
Stay informed and get updates
Get the latest updates on the treatment plant from Christchurch City Council, or subscribe online to receive regular community updates.