More than 830 taxpayer-owned homes are empty as 20,472 hopeful tenants remain on the public housing waiting list.
Figures show that even applicants who are on the priority waiting list - those who are homeless or at risk of homelessness - wait an average 15 months before they get into a State-owned property.
Non-priority applicants have an average wait of two years and 10 months.
The public housing waiting list has shrunk significantly, down from a peak of 24,136 applications in November 2010.
But at the end of last month, 363 public homes were vacant because they were in between tenancies and 472 were considered unlettable because they were undergoing major maintenance and required extensive refurbishment. A further 54 properties were available for allocation or already allocated to new tenants.
According to the Department of Housing, which manages 36,700 State-owned properties, about 10 homes are vacated every day and, in some cases, the homes are extensively damaged and can take a long time to bring up to standard.
Housing Minister Bill Marmion said the average time to bring a property up to scratch was 18 days.
Mr Marmion said reasons why properties remained vacant for more than 90 days included remediation after the rare discovery of a clandestine drug lab, the removal of materials containing asbestos, major plumbing works in older properties and full kitchen, bathroom or laundry renovations.
Mr Marmion said the public housing waiting list had been falling because more than twice as many social housing homes had been delivered under the current State Government than during eight years under WA Labor.
He said changes in the housing market had also likely helped more people find their own home.
But he conceded that the long wait for priority applicants meant there was more work to be done.
The Government had a strategy to increase affordable housing.
Shadow housing minister Fran Logan said the "disgraceful" number of vacancies showed the Government clearly needed to make getting the 40,000 men, women and children on the waiting list back into housing sooner a priority.
He said maintenance of properties needed to be managed better.