Almost 20,000 homes have been put on notice for future flood risk after a water authority released revised flood maps.
More than 19,000 homes in Banyule City Council in Melbourne's northeast and Moonee Valley City Council in the city's northwest have been flagged as being newly at risk during a significant rainfall event in Melbourne Water's draft flood maps.
In Banyule, which encompasses suburbs such as Greensborough, Ivanhoe and Heidelberg, about 7400 homes, or just over one-in-10 properties, could be affected.
About 44 per cent of impacted properties - 3256 - are categorised in the two lowest zones, which is generally considered safe for people and building.
"For those households, the practical response is awareness and preparedness rather than significant action," the authority said.
