Sewage has likely been leaking into Wellington's harbour for years.

A wastewater pipe on Manners Street had been incorrectly connected to the stormwater network and spewed waste into the harbour.

The issue has been fixed, but it's once again brought the capital's water systems into question.

Wellington's Chief Wastewater Advisor, Steve Hutchinson, says it's not a rare occurrence as the region has a large network.

He says there's more than 150-thousand connections for wastewater and stormwater, so they're reliant on proper inspections -- and this specific inspection was likely years ago.

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