HomeMagazineBoat WorldAnother Mahurangi spill raises serious questions for Watercare

Another Mahurangi spill raises serious questions for Watercare

Second overflow in just over a month leaves harbour users frustrated and oyster farmers angry and financially exposed.

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Mahurangi oyster farmers are facing yet another blow after a fresh wastewater overflow hit the river last week. It comes just three weeks after the major 1,200-cubic-metre spill that shut down harvesting, triggered a million-dollar relief package, and damaged confidence in the region’s aquaculture systems.

Watercare confirmed an engineered overflow at Elizabeth Street on the evening of 18 November, triggered by 53mm of overnight rain. For locals, that number is galling.

“Fifty-three millimetres is not an extreme event. The network should cope with that,” says Mahurangi Oyster Farmers Association president Lynette Dunn. “When sensors fail and basic information goes missing, farmers lose confidence in the process.”

The overflow began at 6.05pm, but exactly how long it continued is unclear. A key monitoring sensor failed at 1am, leaving Watercare unable to confirm the full duration. Their current estimate sits at about 86 cubic metres of discharge.

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Compounding the issue, an alarm sounded at the Palmer Street pump station for more than an hour. Watercare has not yet confirmed whether that site also overflowed.

Earlier this month, Aquaculture New Zealand and the New Zealand Oyster Industry Association secured an urgent $1 million relief agreement with Watercare for losses linked to the October spill. An independent assessor is now reviewing the full financial impact on farmers, including longer-term damage to market confidence.

Damaged shellfish grounds

“These events don’t just affect harvests—they undermine trust in the entire industry,” says AQNZ chief executive Teena Hale Pennington.

For growers, the repeated failures are hitting hard: harvest delays, environmental harm, slipping customer confidence, and the emotional toll of yet another uncertainty-filled season.

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Industry groups say they will continue pushing for full compensation by the end of the year. Meanwhile, farmers wait — again — for clean water readings, clear answers, and a reliable fix to a system that has now failed twice in less than a month.

Mahurangi oyster farmers despair at Watercare’s biggest sewage spill yet

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