Knox Council has reminded residents via their news updates page that Quarry Lake is still hosting levels of bacteria considered risky to animal and human health.
Testing at the Ferntree Gully Quarry Reserve Lake detected E. coli and Enterococci bacteria in the water on 15 December 2025 as not suitable for swimming and not to be ingested.
With signage around the lake warning visitors not to swim, fish, or let their dogs enter the water, the issue has been ongoing since 6 November 2025 until further notice.
Knox Council will continue to monitor the water quality, testing weekly until mid-April and will update the community when it returns to safe levels.
For more information, see the Knox Council website or contact their Stormwater team on 9298 8000.
