Montrose (Victoria) Taste and Odour, Ethyl Benzene, Xylene

14 July 2022, Montrose water sampling locality (WQZ 56)

On 14 July 2022, Montrose High Level Reservoir was returned to service following maintenance. Over the next 6 days, Yarra Valley Water received widespread water quality complaints relating to taste and odour. Customers described the water as having a chemical taste and odour.

Investigations determined that the water was imparted with a taste and odour due to chemicals leaching from a new internal coating that was applied as part of maintenance. There is no risk to public health; all health guidelines as specified in the Australian Drinking Water Guidelines were met. The results for Ethylbenzene and Total Xylene were slightly above the aesthetic limit for these parameters, hence the chemical taste and odour in the water.

Yarra Valley Water verbally informed the Department of Health of the complaints on 18 July 2022. Section 22 report was submitted on 19 July 2022. The Department of Health were informed that the reservoir was returned to service on 3 October 2022 after extensive cleaning. Subsequent water samples indicated that there was a minor exceedance in aesthetic quality.

A decision was made to keep the reservoir in service due to water supply risks as a result of extreme weather, which the Department of Health were engaged for consultation on 12 October 2022. A communication plan was developed to manage potential widespread complaints. Between 14 July to 28 October 2022, Yarra Valley Water received 46 taste and
odour complaints. The reservoir was taken offline again on 31 October 2022. After further
cleaning, the reservoir was returned to service on 16 November 2022. Yarra Valley Water provided continuous updates to the Department of Health during this period.