The Matamata-Piako District Council has been fined almost $50,000 for unlawfully discharging wastewater into the environment.
In 2018, the council was alerted to a damaged a pipe in Morrinsville, where wastewater was gushing into a gully and the Piako river.
After it was decided that repairs could not be completed until the following day, council staff left the site without stopping the leak.
About 100,000 litres of untreated wastewater, containing sewage, flowed into the gully overnight causing a 'moderately serious' level of contamination to the river.
The incident was investigated by the Waikato Regional Council, who found the Matamata-Piako District Council could have stopped the leak, even while repairs were halted.
During sentencing in the Hamilton District Court, Judge Melanie Harland said the council had the responsibilty to seek the best advice available in situations like this.
She said that in this instance, the relevant expert was present with equipment, that if used, would have stopped the discharge.