California Code, Health and Safety Code - HSC § 1520.5

(a) The Legislature hereby declares it to be the policy of the state to prevent overconcentrations of residential facilities that impair the integrity of residential neighborhoods. Therefore, the department shall deny an application for a new residential facility license if the department determines that the location is in a proximity to an existing residential facility that would result in overconcentration.

(b) As used in this section, “overconcentration” means that if a new license is issued, there will be residential facilities that are separated by a distance of 300 feet or less, as measured from any point upon the outside walls of the structures housing those facilities. Based on special local needs and conditions, the department may approve a separation distance of less than 300 feet with the approval of the city or county in which the proposed facility will be located.

(c) At least 45 days prior to approving any application for a new residential facility, the department, or county licensing agency, shall notify, in writing, the planning agency of the city, if the facility is to be located in the city, or the planning agency of the county, if the facility is to be located in an unincorporated area, of the proposed location of the facility.

(d) Any city or county may request denial of the license applied for on the basis of overconcentration of residential facilities.

(e) Nothing in this section authorizes the department, on the basis of overconcentration, to refuse to grant a license upon a change of ownership of an existing residential facility when there is no change in the location of the facility.

(f) Foster family homes and residential facilities for the elderly shall not be considered in determining overconcentration of residential facilities, and license applications for those facilities shall not be denied upon the basis of overconcentration.

(g) Transitional shelter care facilities and temporary shelter care facilities shall not be considered in determining overconcentration of residential facilities, and license applications for those facilities shall not be denied upon the basis of overconcentration.