Plumbing or Domestic Water Systems

The domestic water system is the internal plumbing system for the purpose of providing potable water to consumers within the building. The domestic water system begins after the water meter and includes all piping, fixtures and apparatus for the delivery of potable water. The domestic water system is connected to the public water system distribution system by the water service pipe, which transports water to the water meter.

Public health officials and the plumbing industry have been concerned about cross-connections and backflow prevention in the plumbing system for many years.  The plumbing industry has established pluming codes for the control of cross-connections and has advocated the separation of water piping and the sewer piping to reduce the possibility of contamination of the potable water. The plumbing code addresses the size of water service pipe to include pressure requirements. The plumbing codes deals with all aspects of water supply and distribution such as but not limited to pressures requirements, velocity limitations, material, and water demands.  Water distribution system design criteria are addressed in the plumbing codes as is the protection of the potable water supply.  All plumbing fixtures shall be installed to prevent backflow from occurring. The use of air gap separation has been in place and has functioned as the best methods for controlling cross-connections.  The plumbing codes state that the domestic water system shall be designed to prevent cross-connection incidents by the installation of backflow prevention devices on fixtures, appliances and equipment that are connected to the potable water system and could cause a threat to the public health. The domestic water system should not be a public health treat because according to the plumbing codes all cross-connection shall be controlled. Therefore, if a facility is in compliance with the plumbing code the potable water is safe to drink and there is no a public health threat and no need for the public water system to require the installation of a backflow preventing device on the service line.   However, plumbing installers may not be aware of the danger of cross-connections and are making changes to the plumbing not realizing that the water may flow in a reverse direction causing a cross-connection incident. To control cross-connections, the plumbing industry needs to take a more active role in the enforcement of the plumbing codes as they related to cross-connections. Every facility should be periodically surveyed for cross-connections and a certificate of compliance shall be issued to the facility owner by the public water system or plumbing officials or both.