What is defined as one or more rooms designed for living, sanitary, and sleeping facilities for a single family?

The term that best describes one or more rooms designed for living, sanitary, and sleeping facilities for a single family is "Dwelling Unit." This designation encompasses the entire unit utilized by a family for daily living activities, including essential facilities such as bathrooms, kitchens, and sleeping areas.

In the context of building codes and regulations, a dwelling unit is specifically defined to ensure clarity in legal, safety, and construction terms. It provides a standardized understanding of what constitutes a household living space, which is essential for code compliance, zoning laws, and various assessments related to housing.

The other terms, while related, do not encapsulate the complete definition as specifically as "Dwelling Unit." For example, "Living Space" might refer more broadly to any area where people reside without the explicit focus on the unit as a self-contained living environment. "Family Residence" also implies a home but may not carry the same technical definition within legal frameworks. "Residential Unit" could refer to any unit in a building such as apartments but lacks the specificity associated with a single family’s living space that a dwelling unit provides.