Cal. Const. art. XXII, § 1

The State of California and all other governmental entities, including, but not limited to, cities, counties, cities and counties, school districts and other special districts, local and regional agencies and joint power agencies, shall be allowed to contract with qualified private entities for architectural and engineering services for all public works of improvement. The choice and authority to contract shall extend to all phases of project development including permitting and environmental studies, rights-of-way services, design phase services and construction phase services. The choice and authority shall exist without regard to funding sources whether federal, state, regional, local or private, whether or not the project is programmed by a state, regional or local governmental entity, and whether or not the completed project is a part of any state owned or state operated system or facility.