Western Region Water Cooperation (WRWC) occupied the premises situated at 499 Eynesbury Rd, Eynesbury (Lot 561, Plan PS543210).

On 28 April 2018, EPA were informed by WRWC of a sewerage spill at the premises which had resulted in sewerage entering the Werribee River. EPA were informed that the spill had been flowing for 96 hours prior to ceasing at approximately 7:30pm on 27 April 2018.

The spill had occurred as a result of a 1 metre longitudinal split in the underground rising main sewerage pipe. The liquid from the spill spread overland and some of that liquid overflowed into a nearby drainage system which subsequently entered the Werribee River. The spill volume which escaped from the damaged rising main pipe was estimated to be approximately 2 mega litres (or 2 million litres).

An investigation conducted by WRWC into the cause of the spill concluded that the probable cause of pipe's failure was either a) over exposure of the pipe to sunlight either before or during construction, or b) the section of pipe which had failed did not in fact appear to match the specification in the design documentation (i.e. the incorrect pipe was installed).

At the time of the spill WRWC had various mechanisms in place to detect discrepancies in pipeline flow, however due to infrastructure upgrade works taking place at the time, the spill was not detected for some days after the incident.