As used in this chapter:
Air-Gap Separation (AG).A physical separation of at least two (2) times the effective pipe diameter between the free-flowing discharge end of a potable water supply pipeline and the flood level of an open or nonpressurized receiving vessel and in no case less than one (1) inch.
Approved Water Supply.A water source that has been approved by the State Water Board for domestic use in a public water system and designated as such in a domestic water supply permit issued pursuant to section 116525 of the CHSC.
Auxiliary Water Supply.Any water supply located on the premises of, or available to, the water user other than the approved water supply.
Backflow.A flow condition, caused by a differential in pressure, that causes the undesired or unintended reversal of flow of water or other liquids, gases, mixtures or substances into the distributing pipes of a potable supply of water from any source or sources other than an approved water supply source. Back siphonage is one cause of backflow; back pressure is the other cause.
Backflow Prevention Assembly.A mechanical assembly designed and constructed to prevent backflow, such that while in-line it can be maintained and its ability to prevent backflow, as designed, can be field tested, inspected and evaluated.
Contamination.A degradation of the quality of the potable water by any foreign substance which interferes with the usefulness or quality of the water.
Cross-Connection.Any actual or potential connection or structural arrangement between a potable water system used to supply water for drinking purposes, including a piping system connected to the public water system and located on the premises of a water user or available to the water user, and any source or systems containing unapproved water or a substance that is not or cannot be approved safe, wholesome and potable. Bypass arrangements, jumper connections, removable sections, swivel or changeover devices or other devices through which backflow could occur shall be considered cross-connections.
Distribution System.As defined in section 63750.
50 of CCR, Title 22, Division 4, Chapter
13, any combination of pipes, tanks, pumps, etc., which delivers drinking water from a source or treatment facility to the consumer.
Double Check Detector Backflow Prevention Assembly (DCDA).A double check valve backflow prevention assembly that includes a bypass with a water meter and double check backflow prevention assembly, with the bypass's water meter accurately registering flow rates up to two gallons per minute and visually showing a registration for all rates of flow.
Double Check Valve Backflow Prevention Assembly (DC).An assembly composed of two independently acting and internally loaded check valves, including tightly closing resilient seated shutoff valves attached at each end of the assembly and fitted with properly located resilient seated test cocks that enable accurate field testing of the assembly.
Hazard Assessment.An evaluation of a user premises designed to evaluate the types and degrees of hazard at a user's premises.
High Hazard Cross-Connection.A cross-connection that poses a threat to the potability or safety of the public water supply. Materials entering the public water supply through a high hazard cross-connection are contaminants or health hazards.
Low Hazard Cross-Connection.A cross-connection that has been found to not pose a threat to the potability or safety of the public water supply but may adversely affect the aesthetic quality of the potable water supply. Materials entering the public water supply through a low hazard cross-connection are pollutants or non-health hazards.
Health Agency.The California Department of Health Services, or the local health agency with respect to a small water system.
Premises Containment.The protection of a public water system's distribution system from backflow from a user's premises through the installation of one or more air gaps or BPAs, installed as close as practical to the user's service connection, in a manner that isolates the water use'rs water supply from the public water system's distribution system.
Pressure Vacuum Breaker Backsiphonage Prevention Assembly (PVB).An assembly containing an independently operating internally loaded check valve and an independently acting loaded air inlet valve located on the discharge side of the check valve. The assembly is to be equipped with properly located resilient seated test cocks and tightly closing resilient seated shut-off valves attached at each end of the assembly that enable accurate field testing of the assembly.
Reduced Pressure Principle Backflow Prevention Assembly (RP).An assembly containing two independently acting internally loaded check valves together with a hydraulically operating, mechanically independent pressure differential relief valve located between the check valves and at the same time below the upstream check valve. The unit shall include properly located resilient seated test cocks and tightly closing resilient seated shut-off valves at each end of the assembly to enable accurate field testing of the assembly.
User Premises.Any and all areas on a water user's or customer's property which is served or has the potential to be served by the public water system.
Water Supplier.A person or entity who owns or operates a public water system.
Water User.Any person obtaining water from an approved water supply system.
(Ord. 16-318, 2016; Ord. 25-0383, 8/11/2025)