Cal. Penal Code § 13732

(a) The Legislature finds and declares that a substantial body of research demonstrates a strong connection between domestic violence and child abuse. However, despite this connection, child abuse and domestic violence services and agencies often fail to coordinate appropriately at the local level. It is the intent of the Legislature in enacting this section to improve preventative and supportive services to families experiencing violence in order to prevent further abuse of children and the victims of domestic violence. It is the further intent of this section that child protective services agencies develop a protocol which clearly sets forth the criteria for a child protective services response to a domestic violence related incident in a home in which a child resides. (b) Commencing January 1, 2003, child protective services agencies, law enforcement, prosecution, child abuse and domestic violence experts, and community-based organizations serving abused children and victims of domestic violence shall develop, in collaboration with one another, protocols as to how law enforcement and child welfare agencies will cooperate in their response to incidents of domestic violence in homes in which a child resides. The requirements of this section shall not apply to counties where protocols consistent with this section already have been developed.