This paper researches daily household activities and use of space at low cost apartments in Surabaya, Indonesia. In-depth interviews on where & how much space required for activities were done. Functionality is assessed by standards and classified as highly, functional, less, and non-functional. Findings: 13 of 14 apartments have open floor plans with no fixed partitioning; 70% families tend to separate private from the more public space; families entertain, eat, iron, play, work and relax while watching TV in the more public space of multi-functional zone in the unit. Units are concluded less sufficient especially for multi-functional and toilet spaces. It is recommended that unit area of 18 m2 be discontinued. To be functional, developed unit should be at least 32 m2.