ORC lifts Central Otago sewage abatement notices

The Central Otago District Council (CODC) says that the district’s wastewater treatment plants are showing an improvement in complying with resource consent conditions for river discharges.

CODC has seven wastewater treatment plants located at Cromwell, Alexandra, Lake Roxburgh Village, Roxburgh, Omakau, Ranfurly and Naseby.

In January 2023, the Otago Regional Council (ORC) audited the wastewater treatment plants and identified several maintenance issues and non-compliances with resource consent conditions, resulting in issuing of abatement notices for five of the CODC’s plants.

The ORC carried out an audit in March this year, with the results showing a trend of improvement in recent years.

In a report to the Council meeting today (Wednesday 28 May 2025), CODC Sampling and Compliance Monitoring Team Leader Joyce Thomas said of the five, Alexandra and Cromwell’s abatement notices had been lifted and were now compliant for all effluent quality test results (Alexandra in May 2024 and Cromwell July 2024). The remaining three sites (Roxburgh, Ranfurly and Naseby) were still under abatement notices, with due dates for compliance being Roxburgh by 31 August 2025, Naseby by 30 November 2025, and Ranfurly by 30 June 2025.

An aerator at Roxburgh was successfully installed in May, and staff anticipated that this would help achieve compliance with nitrogen limits. Once compliance was achieved, the Council would apply for the cancellation of the abatement notice. Similarly, the non-compliance issues at Naseby had been rectified, and cancellation of the abatement notice applied for, which was awaiting a response. 

The report states that ORC acknowledges these improvements during the audits, noting the consistent efforts made by Council staff to address instances of non-compliance. Regular communication with the regulator and proactive responses to compliance issues were specifically recognised as contributing factors to the positive audit outcomes. 

A full report of each plant’s status can be found in the agenda item: Agenda of Council meeting - Wednesday, 28 May 2025

Central Otago Mayor Tamah Alley said it was gratifying to read about the level of compliance but commented that there was still room for improvement.

“I think it’s probably worth noting that a fair amount of our non-compliance relates to storm water cross connections."

“It’s also worth noting that this council is asking the government for assistance to force people to make these changes; we have asked nicely for people to stop discharging  stormwater from their house into our system because it is costing everyone.

“If people have had a letter from us, please know that this is not going to go away, that we need you to fix the issue if this is your house.”

Letters had been sent to properties in Alexandra and Cromwell in 2021 because of the scale of work being undertaken in those towns.

CODC Group Manager - Three Waters Julie Muir said stormwater going into the system was one of the most difficult issues to follow up and contributed to problems during heavy rain events.

In general discussion, councillors talked about changes to consent conditions under the new regulations, and the potential confusion for the public because the changes were transitioning, and the increased monitoring costs to comply with discharge conditions.