(a) Except as provided by Subsection (b), a municipality may not adopt or enforce a zoning ordinance, rule, or other regulation that limits the number of people who may occupy a dwelling unit based on:
(1) age;
(2) familial status;
(3) occupation;
(4) relationship status; or
(5) whether the occupants are related to each other by a certain degree of affinity or consanguinity.
(b) A municipality may impose a limit on the number of occupants of a dwelling unit that is not more restrictive than:
(1) one occupant per sleeping room with a minimum floor area of 70 square feet; and
(2) one additional occupant for each additional 50 square feet of floor area in the same sleeping room.