Plumbing Industry Responsibilities
The installation of a backflow prevention device on the water service line alone is not considered cross-connection control by the plumbing code or plumbing code officials. The plumbing code requires cross-connections to be controlled where they exist and the installation of a backflow prevention device on all potable water fixture outlets when necessary. The plumbing codes contain sections directly dealing with the protection of potable water and the control of cross-connections. Protection of the potable water system is an important aspect of the pluming code. It is the responsibility of the pluming industry to prevent contamination of the domestic water system thus protecting the public water system.
The plumbing code requires a potable water supply system to be designed, installed and maintained in such a manner as to prevent contamination from non-potable liquids, solids or gases from being introduced into the potable water supply through cross-connections or any other piping connection to the system. According to the plumbing codes, plumbing shall be installed to prevent backflow and a cross-connection incident. Individuals using water rely on the water and plumbing industry to provide them with safe potable water for use no matter where or how it is used. The primary responsibility for the quality of water delivered through the internal domestic system is the plumbing industry. However, the public water system needs to be aware of the consequences and the shortcoming of the plumbing industry such as lack of enforcement and compliance of the plumbing codes relating to controlling cross-connections. Therefore, it shall be the responsibility of public water system to make this situation know to the building or facility owner.
When a backflow prevention device is installed on the service line upstream of a hot water heater source, water that is heated will not be able to expand which will cause an increase in water pressure. To prevent this increase pressure from causing damage to the hot water system, a thermal expansion tank shall be installed pursuant to the plumbing codes. A relief valve is not considered a thermal expansion device because continuously dripping for the valve can cause the valve to fail due to build-up of minerals in the water.
Water is not compressible and heated water expands. Backflow devices eliminate a path for the expanding water creating high pressure in piping system. Heated water can expand by one-half gallon in a 40-gallon hot water heater.
The plumbing codes require annual inspections of all backflow prevention device assemblies and air gaps to determine if they are operable. The plumbing codes also requires all reduced pressure principle backflow prevention assemblies, double check valve assemblies, pressure vacuum breaker assembles, reduced pressure detector fire protection backflow protection assemblies, double check detector fire protection backflow prevention assemblies, hose connection backflow preventers and spill-proof vacuum breakers to be tested at the time of installation, immediately after repairs or relocation and at least annually.