A five-month investigation into July's water main break which saw an estimated 800,000 litres of wastewater flow into Lake Taupō has now concluded.
Following the investigation, the Waikato Regional Council said it has decided not to initiate prosecution over the incidents.
The initial incident on July 2 saw a burst underground water main erode a section of cliff face, which caused a footpath to collapse onto a sewerage pipe, resulting in it breaking and discharging wastewater to the lake. The spill included raw sewage.
As a result of the incident, Taupō District Council tried to shift the water and wastewater infrastructure back from the cliff face but during the operation on July 16 more wastewater poured into the lake.
"Our investigation has determined that it would not be appropriate for any person or entity to face formal enforcement action,” said Waikato Regional Council’s investigations manager Patrick Lynch.
“We take our regulatory responsibilities very seriously. We have a strong reputation of taking enforcement action where it is warranted and legally appropriate to do so, regardless of who is involved,” he said. “But in this instance we will not be pursuing a prosecution for the incidents.”
He said this was a unique set of circumstances.
"There is no doubt this was, at the time, a terrible incident with far-reaching impacts on iwi, residents, water users and visitors."