Cal. Health & Saf. Code § 116460
No person shall operate a public water system without an emergency notification plan that has been submitted to and approved by the department. The emergency notification plan shall provide for immediate notice to the customers of the public water system of any significant rise in the bacterial count of water or other failure to comply with any primary drinking water standard that represents an imminent danger to the health of the water users.
No permit, variance, or exemption may be issued or amended under this chapter until an emergency notification plan has been approved by the department.
The department shall adopt regulations to implement the provisions of this section. The regulations may provide for the exclusion of public water systems from the requirements of this section when, in the judgment of the department, the exclusion will best serve the public interest.
Ca. Health and Saf. Code § 116460