Deciding when a house is underutilised, occupied efficiently or crowded is important in determining social policy about housing. With people living in ‘severely’ crowded dwellings—the fastest growing category of homelessness—it is important to understand exactly what is meant when we refer to crowding.

For Australian agencies, including state housing authorities and the Australian Bureau of Statistics (ABS), crowding is defined by the principles established in the Canadian National Occupancy Standard (CNOS).  The Standard is grounded on measuring the number of people per bedroom for each dwelling, and is based on the ‘norms’ of sleeping and living in a western nuclear family culture. Rather than a simple ‘crowding’ definition based on how many people are living in each bedroom, it is based on a nuanced understanding of the social and family relationships of those in the dwelling.

CNOS assesses the bedroom requirements of a household based on the following criteria:

CNOS criteria Bedroom requirements


No more than two people per bedroom.

Gender and age

Children aged under 5, of the same or different genders, can share a bedroom.

Children aged over 5 and under 18, of the same gender, can share a bedroom.

Children aged over 5, of different genders, should not share a bedroom.

Relationship status and age

Couples and their children should not share a bedroom.

A household of one unattached individual may occupy a bed-sit.

Single household members, aged over 18, should have their own bedroom.

Source: AHURI Final Report 194: Australian Indigenous house crowding 

In particular, CNOS is used for determining the number and circumstances of people who are experiencing homelessness. The ABS defines a person as homeless if their current living arrangement:

  • is in a dwelling that is inadequate;
  • has no tenure, or if their initial tenure is short and not extendable; or
  • does not allow them to have control of, and access to space for social relations.

For these reasons the ABS includes persons living in 'severely' crowded dwellings as one of the six operational groups of homeless persons. A 'severely' crowded dwelling is one which needs four or more extra bedrooms to house the people living there in accordance with the principles of CNOS.

The ABS also counts people who are at risk of becoming homeless, such as people who are marginally housed. This category includes people living in ‘other crowded dwellings’, which is defined as a dwelling that needs three more bedrooms based on the CNOS principles.