The type of protection that shall be provided to prevent backflow into the public water supply system shall be commensurate with the degree of hazard, actual or potential, that exists on the water user’s premises. Unprotected cross-connections with the public water supply are prohibited. The type of backflow prevention assembly that may be required (listed in decreasing level of protection) includes: air-gap separation, reduced pressure principle backflow prevention assembly, and a double check valve assembly. The water user may choose a higher level of protection than required by the water supplier. The minimum types of backflow protection required to protect the approved water supply at the user’s water connection to premises with varying degrees of hazard are listed in Table 1, Section 7604, Title 17, CCR. Situations that are not covered in Table 1 shall be evaluated on a case-by-case basis, and the appropriate backflow protection shall be determined by the city. (Ord. 712 §1, 2020).