Cal. Gov. Code § 66319

An accessory dwelling unit that conforms to Section 66314 shall be deemed to be an accessory use or an accessory building and shall not be considered to exceed the allowable density for the lot upon which it is located, and shall be deemed to be a residential use that is consistent with the existing general plan and zoning designations for the lot. The accessory dwelling unit shall not be considered in the application of any local ordinance, policy, or program to limit residential growth.