Cal. GOV § 8607.2

(a) All public water systems, as defined in subdivision (f) of Section 116275 of the Health and Safety Code, with 10,000 or more service connections shall review and revise their disaster preparedness plans in conjunction with related agencies, including, but not limited to, local fire departments and the Office of Emergency Services to ensure that the plans are sufficient to address possible disaster scenarios. These plans should examine and review pumping station and distribution facility operations during an emergency, water pressure at both pumping stations and hydrants, and whether there is sufficient water reserve levels and alternative emergency power, including, but not limited to, onsite backup generators and portable generators.

(b) All public water systems, as defined in subdivision (f) of Section 116275 of the Health and Safety Code, with 10,000 or more service connections following a declared state of emergency shall furnish an assessment of their emergency response and recommendations to the Legislature within six months after each disaster, as well as implementing the recommendations in a timely manner.

(c) The Office of Emergency Services shall establish appropriate and insofar as practical, emergency response and recovery plans, including mutual aid plans, in coordination with public water systems, as defined in subdivision (f) of Section 116275 of the Health and Safety Code, with 10,000 or more service connections.