Christchurch Wastewater Treatment Plant update

Monday 16 February 

Where we're at 

It was a positive weekend at the plant, with continued signs of improvement across the ponds. Dissolved oxygen levels and algae recovery have both trended upward, and odour levels have eased noticeably over the past two days. The weather has played a big part in helping stabilise pond conditions.

We know some of you will have been dealing with the Boil Water Notice for the Rawhiti water supply zone. This notice has now been lifted for everyone, except approximately 20 properties who will need to keep boiling their water. We will be communicating with these residents directly. You can find more information on our website.

Aerator update – Pond 2A

One of the new aerators on Pond 2A stopped operating on Sunday. Our operations team has prioritised this and is working on repairs. We will return it to service as quickly and safely as possible to maintain momentum in pond recovery.

Planning for the long-term

Staff are actively working with our specialist consultant on the longer-term resilience plan for the ponds. This work is progressing and focuses on ensuring sustained performance, robustness, and better response capability during challenging conditions.

Upcoming rain event and potential pond impacts

As you know, cooler weather and rainfall can influence how the pond biology behaves. Our team has been watching the forecasts closely and is planning ahead to manage the ponds through this weather event.

With algae and dissolved oxygen levels now heading in the right direction, we’ll be doing everything we can to maintain these gains and protect the progress made over the past several days. Staff will be onsite monitoring conditions throughout the rain.

Community outreach – next steps

Thank you again to everyone who spoke with us during our neighbourhood visits last week. Your feedback has been incredibly valuable and is directly shaping the next phase of support options. We expect to be able to share more later this week about the next steps.

When we’ll be in touch again

Unless conditions change significantly, we’ll be back in touch on Thursday with another update, including the next round of hydrogen sulphide graphs.

Odour status 

There is no change to the pond status map today. We’ll continue to monitor the improvements closely and update the community as conditions evolve.

Latest hydrogen sulphide monitoring 

The latest hydrogen sulphide graph shows that H₂S remains present at detectable levels. Our teams will continue to monitor readings closely and provide updates as trends develop.

Stay updated

We want everyone to be able to stay updated on what's happening at the Christchurch Wastewater Treatment Plant, and we regularly post new information on ccc.govt.nz/wastewaterfire 

You're welcome to send this update to your networks. If you know someone in the community who doesn’t have email or internet access, please print this newsletter off and pass it to them.

If you know of anyone who would like to receive this e-newsletter they can subscribe online. 

If you have any questions, or would like further information on the project, please call us on 03 941 8999 or 0800 800 169 or email wastewater@ccc.govt.nz  

Thanks for your patience and understanding. We’ll be in touch again soon.