The severe failure of the plant has resulted in the continuous discharge of untreated wastewater along Wellington’s South Coast for several months.
In the latest update, Wellington Water confirmed that the February flooding inflicted damage on essential mechanical components, including the odour treatment, sludge pumping, and aeration equipment. Additionally, the electrical systems such as the PLC (Programmable Logic Controller), MCC (Motor Control Centre), control instruments, and cabling were affected, which comprise the core operational systems of the plant.
The extent of the damage requires repairs or replacements for approximately 14.5km of cables, according to the water services provider.
The damage assessment was conducted for insurance purposes, and Wellington Water has indicated that a comprehensive report will be released to the public “as soon as appropriate.”
“The report may need to be reviewed as part of any potential insurance claim/s before being released to the public,” they stated.
Nearly two months post-breakdown, untreated sewage continues to flow into the sea due to the plant’s ongoing failure.
An earlier report from Wellington City Council suggested that air trapped in the pipes might have caused the failure.
The day following the failure, on February 5, Wellington Water commissioned an engineering report to determine how to maintain plant operations during recovery efforts.
Experts from Stantec utilized software to create a hydraulic model of the plant, simulating the probable water flow during the initial failure.
Although the report was not intended to pinpoint the cause, it provided valuable insights, according to Wellington Mayor Andrew Little’s office at the time.

