A "swarm" of earthquakes could have caused sewage to flow into Lake Taupō, the local mayor has suggested.
Wastewater began flowing into the lake on Tuesday afternoon, with pictures from the scene showing a large brown stain spreading across blue water.
Taupō Mayor Dave Trewavas told The AM Show crews had worked through the night and wastewater is no longer getting into the lake.
He's still asking local residents to avoid flushing the toilet though, and said an update on that situation will be provided later in the morning.
Attention is now turning towards what caused the pipe to fail in the first place and Trewavas believes nature is at fault.
"I've just had a look at the pipes under the ground, they're quite new, in actual fact they have a hundred-year lifespan of pipe and its only about year 18 so they've got 82 years of life left in them," he said.
"So no problems with the infrastructure... it could be those quiet little earthquakes that keep happening down here. We are pretty hot under the ground here so all sorts of things come into play."
Trewavas said there had been a "swarm of earthquakes" over the last few months, which may have led to instability in the ground.
The wastwater is now headed away from Taupō, which could be an issue for anyone living down river from the city.
"[The break] is very close to the Waikato River mouth, so dare I say it we'll be sending it your way," Trewavas said.
"If it was in the middle of the lake or down the southern shores it would be devastating because it would come straight through across the lake. This way it's moving pretty fast down the Waikato River."
Roseline Klein, head of value for Auckland's Watercare, later told The AM Show there is no risk to health for Auckland communities.
Newshub.
Have you been impacted by the sewage pipe spill in Taupō? Please get in touch with Newshub reporter Cleo Fraser - cleofraser@mediaworks.co.nz or 09 928-9050.
