California Code, Health and Safety Code - HSC § 11834.23

(a) Whether or not unrelated persons are living together, an alcohol or other drug recovery or treatment facility that serves six or fewer persons shall be considered a residential use of property for the purposes of this article. In addition, the residents and operators of the facility shall be considered a family for the purposes of any law or zoning ordinance that relates to the residential use of property pursuant to this article.

(b) For the purpose of all local ordinances, an alcohol or other drug recovery or treatment facility that serves six or fewer persons shall not be included within the definition of a boarding house, rooming house, institution or home for the care of minors, the aged, or persons with mental health disorders, foster care home, guest home, rest home, community residence, or other similar term that implies that the alcohol or other drug recovery or treatment home is a business run for profit or differs in any other way from a single-family residence.

(c) This section does not forbid a city, county, or other local public entity from placing restrictions on building heights, setback, lot dimensions, or placement of signs of an alcohol or other drug recovery or treatment facility that serves six or fewer persons as long as the restrictions are identical to those applied to other single-family residences.

(d) This section does not forbid the application to an alcohol or other drug recovery or treatment facility of any local ordinance that deals with health and safety, building standards, environmental impact standards, or any other matter within the jurisdiction of a local public entity. However, the ordinance shall not distinguish alcohol or other drug recovery or treatment facilities that serve six or fewer persons from other single-family dwellings or distinguish residents of alcohol or other drug recovery or treatment facilities from persons who reside in other single-family dwellings.

(e) A conditional use permit, zoning variance, or other zoning clearance shall not be required of an alcohol or other drug recovery or treatment facility that serves six or fewer persons that is not required of a single-family residence in the same zone.

(f) Use of a single-family dwelling for purposes of an alcohol or other drug recovery facility serving six or fewer persons shall not constitute a change of occupancy for purposes of Part 1.5 (commencing with Section 17910) of Division 13 or local building codes. However, this section does not supersede Section 13143 or 13143.6, to the extent those sections are applicable to alcohol or other drug recovery or treatment facilities serving six or fewer residents.