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Summarised by Centrist
Wellington’s main wastewater treatment plant initially failed outright, sending an estimated 70 million litres of untreated sewage a day into the capital’s south coast since Wednesday morning.
The Moa Point Treatment Plant was shut down after sewage backed up in its 1.8km outfall pipe, flooding the lower levels of the facility and forcing operators to divert raw wastewater directly into the ocean.
The discharge has affected beaches along the South Coast, triggering public warnings to stay out of the water, keep dogs away and avoid gathering seafood.
Mayor Andrew Little described the breakdown as a “catastrophic failure” and an “environmental disaster”, saying a plant serving a city the size of Wellington should never be able to “completely stop”.
“This is a sewage plant processing the sewage for a big city, and it has completely failed,” he said, calling for an independent inquiry into how the system collapsed.
While officials said wastewater volumes were within design limits, Little acknowledged something had gone seriously wrong, pointing to a blockage or system failure that caused sewage to back up rather than flow out to sea as intended.
The scale of the failure has left normally busy beaches deserted, with Wellington Water staff stationed along the coast warning people away.
Wellington Water says some progress has been made, with screened wastewater now being discharged through the offshore outfall pipe into the Cook Strait, rather than directly onto South Coast beaches.
The pipe is only partially operational, handling most average daily flows but forcing continued near-shore discharges during peak periods. Officials say offshore discharge allows greater dilution, but health warnings remain in place and no timeframe has been given for a full restoration.
Locals told reporters the water looked “gross”, “toxic” and “unacceptable”, with some saying the incident was just the latest in a string of infrastructure problems across the city.
