The NSW Environment Protection Authority investigated the spill at the Out St premises after the company reported the incident.

EPA north branch acting director Brett Nudd said the spill was caused by multiple equipment failures at the site and would have been prevented had the company carried out scheduled maintenance.

“A pump failure resulted in wastewater overflowing from the first-flush system into an offsite stormwater drain,” Mr Nudd said.

“The high water level alarm also failed, as a result of low voltage in the battery, which had not charged efficiently.”

While there was no evidence of environmental harm, the EPA said it was vital companies effectively maintained their equipment, to avoid putting the environment and local communities at risk.

“To their credit, Baiada took prompt, appropriate clean-up and preventative action in response to the incident and have put considerable funds into rectifying issues with the first-flush system,” Mr Nudd said.

A Baiada spokesman said the company was disappointed the event occurred.

“Following an internal review, we have improved our systems and processes, in order to prevent a similar event happening in the future,” he said.