https://carlbherman.blogspot.com/2020/06/ca-gov-newsom-did-not-sign-executive.html

The Governor is hereby empowered to proclaim a state of emergency in an area affected or likely to be affected thereby when:
(a) He finds that circumstances described in subdivision (b) of Section 8558 exist;  and either
(b) He is requested to do so (1) in the case of a city by the mayor or chief executive, (2) in the case of a county by the chairman of the board of supervisors or the county administrative officer;  or
(c) He finds that local authority is inadequate to cope with the emergency.
~ California Code 8625

“State of emergency” means the duly proclaimed existence of conditions of disaster or of extreme peril to the safety of persons and property within the state caused by conditions such as … epidemic, … which, by reason of their magnitude, are or are likely to be beyond the control of the services, personnel, equipment, and facilities of any single county, city and county, or city and require the combined forces of a mutual aid region or regions to combat … ~ California Code 8558 (b)