This category includes any household member, including foster children, not related to the householder by birth, marriage, or adoption. The following categories may be presented in more detailed tabulations:
- Roomer or Boarder - A roomer or boarder is a person who lives in a room in the household of the householder. Some sort of cash or noncash payment (e.g., chores) is usually made for their living accommodations.
- Housemate or Roommate - A housemate or roommate is a person age 15 years and over, who is not related to the householder, and who shares living quarters primarily in order to share expenses.
- Unmarried Partner - An unmarried partner is a person age 15 years and over, who is not related to the householder, who shares living quarters, and who has a close personal relationship with the householder. Same-sex spouses are included in this category for tabulation purposes and for public use data files.
- Foster Child - A foster child is a person who is under 21 years old placed by the local government in a household to receive parental care. Foster children may be living in the household for just a brief period or for several years. Foster children are nonrelatives of the householder. If the foster child is also related to the householder, the child is classified as that specific relative.
- Other Nonrelatives - Anyone who is not related by birth, marriage, or adoption to the householder and who is not described by the categories given above.
When relationship is not reported for an individual, it is imputed according to the responses for age, sex, and marital status for that person while maintaining consistency with responses for other individuals in the household.