Rats heve completely gnawed through a drainage pipe under a property.

These statistics were revealed today by Archicentre the building advisory service of the Australian Institute of Architects following the research program by its pest inspectors in Victoria, New South Wales and Queensland.

The research showed that Victorian homes had a 22% incidence of possum infestation compared with 2% in New South Wales and Queensland.

Mr Robert Caulfield, Managing Director of Archicentre said that the research was undertaken from pre-purchase housing and pest inspections carried out by Archicentre over the last twelve months.

"91% of homes in Greater Dandenong showed evidence of infestation by rats and mice followed by Banyule (88%), Bayside (87%), Moonee Valley (82%) and Glen Eira (81%). The least affected area was Greater Geelong where only 11% of houses had a problem."

Mr Caulfield also said that 50% of homes in Stonnington showed evidence of possum problems followed by Banyule (41%), Mornington Peninsula (40%), Port Phillip (38%) and Manningham (33%). The least affected areas were Brimbank, Greater Geelong and Hume where Archicentre found no evidence of possum infestation.

"Victorian homes fared worse than their interstate counterparts because the cooler climate encouraged pests to seek warm shelter and Victorians appeared to be more garden conscious making greater use of uncovered compost bins, garden mulch and fertilizers which provided food sources.