The Oberon Council has taken responsibility for releasing untreated sewage into the Fish River. ( ABC Central West: Hamish Cole )
The Oberon Council has to pay $75,000 after releasing untreated sewage into the Fish River.
The local government says the incident did not affect the area's drinking water.
The council is required to conduct tree removal works to improve the river's health.
The mayor of a Central West NSW council has apologised to the community after untreated sewage effluent and toilet paper were released into a river over a nine-day period.
The Oberon Council has entered into an enforceable undertaking with the NSW Environment Protection Authority (EPA) after waste from a pumping station was discharged into the Fish River between September 9 and 17, 2025.
The EPA said samples of the effluent indicated high concentrations of E.coli and faecal bacteria.
Toilet paper, baby wipes and other large items were also observed in the river.
The council will be required to spend $60,000 over three years to remove willow trees along the Fish River and plant native species to improve the stream's health.
It must also pay $15,000 to cover the EPA's costs of investigating the incident.
Oberon Mayor Andrew McKibbon apologised for the incident.
"It was an unacceptable event," he said.
"It was a fault in one of our pumps, so the discharge went out."
Chair of Central Acclimatisation Society, a volunteer group assisting with the restocking waterways with native fish, Wayne Cole said the incident was extremely disappointing and described the penalty imposed by the EPA as a "slap on the wrist".
"We currently treat our rivers like effective drains, we just seem to dump chemicals and rubbish into it," Mr Cole said.
Wayne Cole says the release of untreated sewage by the Oberon Council is "unacceptable". ( ABC Central West: Hamish Cole )
The Fish River supplies water to about 230 properties in the Oberon and Lithgow local government areas.
It also flows into the Macquarie River near Bathurst, which is a popular fishing and swimming spot.
The Fish River feeds into the Macquarie River near Bathurst, while a pipeline takes water to Lithgow and Oberon. ( ABC Central West: Hamish Cole )
Cr McKibbon said there was no evidence the incident affected the region's drinking water supply.
In a statement, the EPA's operations director Scott Kidd said it was "unacceptable" that untreated sewage was discharged.
"Councils have a responsibility to ensure their infrastructure is properly maintained, and issues are reported without delay," he said.
Mr Kidd said native wildlife was likely affected by the incident given the duration of the discharge and the toxicity of the sewage.
"It is likely there was an environmental impact on [the] Fish River, although the extent is difficult to quantify," he said.
Mr Cole says the Oberon Council failed to notify many residents downstream of where untreated sewage was discharged. ( ABC Central West: Hamish Cole )
The Oberon Council said it sent letters to affected residents at the time of the incident and included details in its business papers .
But Mr Cole said many in the community who lived downstream were still unaware of the situation.
"Twelve months ago, a quantity of raw sewage, of high contaminants, was put into the river but was anyone notified downstream?" he said.
The Oberon Council is required to spend $60,000 over three years to help improve the river's health. ( ABC Central West: Hamish Cole )
Oberon Council is in the process of constructing a $18.6 million sewage treatment plant that is expected to come on line next year.
It will replace the existing facility which is more than 65 years old.
Cr McKibbon said the costs associated with the sewage release would impact the council's finances.
"No-one likes having to do this," he said.
"In the end, the works that we will have to do will probably improve considerably the health of the Fish River, over and above what has occurred."
