The registry of people who needed better housing (the housing list) was managed at the local administrative level (the "ispolkom" of the Council of Workers' Deputies) or at the workplace. As a practical matter, the usual entry point was the regional housing office (raizhilotdel). To get on the list there meant that you (or more precisely, your family) was found to be in need of housing, and the government had taken on the obligation of providing it for you, although not immediately. You could wait for many years.
In the 1960s, you could get on the housing list if each member of your family had less than 4.5 square meters of space (the so-called legal norm). You could also join if your building was in a dangerous condition or if people with active tuberculosis were living there. That several families shared a single apartment was not in itself enough of a hardship to warrant a place on the list. The new space would have to provide a minimum of seven square meters per person. But if your family grew or if you took advantage of the increase in the legal norm (first to nine square meters, and then to12), you might celebrate your housewarming only to get back in line.
Certain categories of people had the right to additional space.
When additional space was granted (in practice, this meant either a separate apartment or an additional room in the communal apartment) among the factors taken into account were the time spent on the waiting list, the degree of need, the social value of the work you did, as well as "terms and priorities in the allotment of housing to citizens in accordance with corresponding government decisions." Recommendations from personnel departments and social committees at work were also considered. A bad reference could result in moving a petitioner further down on the list (a type of punishment often used for hoodlums or "parasites"—people who did not work). To quote regulations from the 1970s, "preference in receiving housing from the housing list is given to outstanding laborers, to workers and white-collar employees with seniority at their given plant, organization, or office, with consideration given to length of employment in accordance with the law."
Workers and white-collar employees who were invited to the move to city by their employer, military personnel, and workers at favored enterprises who were building their own housing, had lists of their own.
See the essay Housing in the USSR.