Roommate preferences vs illegal discrimination: the line
It is reasonable to discuss sleep schedules, smoking, pets, cleaning, budget, guests, accessibility needs, and whether a person will share a room. It is not wise to use those needs as a proxy for race, religion, nationality, disability, gender identity, family status, or other protected traits.
Shared-living and owner-occupied arrangements can involve fact-specific exceptions, but they are not a license for discriminatory advertising or screening. Write criteria tied to the actual home and apply them consistently.
If you are unsure, get local fair-housing advice before publishing the listing. The cost of a vague discriminatory phrase can be much higher than rewriting it.
Source: California Civil Rights Department housing guidance.