Just three weeks after the devastating 1,200-cubic-metre wastewater spill into the Mahurangi River, local oyster farmers are grappling with yet another overflow.

On Wednesday 19 November, Watercare Services advised farmers were advised of a discharge from the Elizabeth Street engineered overflow point. Watercare attributed the incident to “very heavy rainfall in Warkworth,” citing 53mm overnight.

The overflow began at 6.05pm on 18 November, but its true duration remains unclear. A monitoring sensor stopped transmitting data at 1.00am, leaving Watercare unable to confirm the full scale of the spill. Current estimates put the discharge at 86 cubic metres.

Lynette Dunn, President of the Mahurangi Oyster Farmers Association says confidence in Watercare’s systems is eroding.

“Fifty-three millimetres is not an extreme event. The network should cope with that,” she says. “Repeated sensor failures and lack of transparency make it challenging for farmers to trust the integrity of Watercare’s processes.”

In addition to the Elizabeth Street discharge, Watercare received an alarm from the Palmer Street pump station lasting around 1 hour and 20 minutes but has not confirmed whether an overflow occurred there.

Earlier this month Aquaculture New Zealand (AQNZ) and the New Zealand Oyster Industry Association (NZOIA) reached an urgent $1 million financial relief agreement with Watercare for losses linked to the 29 October spill.

Teena Hale Pennington, CEO, of AQNZ says an independent assessor will determine the full scale of the farmers’ losses, including long-term reputational impacts on the Mahurangi oyster industry: “These events don’t just affect harvests—they damage customers’ trust and confidence in aquaculture.”

For Mahurangi oyster farmers repeated spills continue to jeopardise livelihoods, damage the river and harbour environment, and cause ongoing financial, emotional and reputational harm.

AQNZ and NZOIA say they will continue to push for Watercare to fully compensate farmers for all losses by year-end.

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