Whenever the Plumbing Inspector determines that it is not practical to protect drinking water systems on premises against entry of water from a source or piping system or equipment that cannot be approved as safe or potable for human use, an entirely separate drinking water system shall be installed to supply water at points convenient for consumers.
Water systems for fighting fire, derived from a supply that cannot be approved as safe or potable for human use shall, wherever practicable, be kept wholly separate from drinking water pipelines and equipment. In cases where the domestic water system is used for both drinking and fire-fighting purposes, approved backflow prevention devices shall be installed to protect such individual drinking water lines as are not used for fire-fighting purposes. Any auxiliary fire-fighting water supply which is not approved for potable purposes, but which is so connected that it may be introduced into potable water piping during an emergency shall be equipped with an approved automatic chlorination machine. It is hereby declared that it is the responsibility of the person or persons causing the introduction of said unapproved or unsafe water into the pipelines to see that a procedure be developed and carried out to notify and protect users of this piping system during the emergency; that special precautions be taken to disinfect thoroughly and flush out all pipelines which may become contaminated before they are again used to furnish drinking water. In the event the means of protection of water consumers is by disinfection of the auxiliary fire-fighting supply, the installation and its use shall be thoroughly reliable.
Potable water pipelines connected to equipment for industrial processes or operations shall be protected by a suitable backflow prevention device located beyond the last point from which drinking water may be taken, which device shall be provided on the feed line to process piping or equipment.
In the event the particular process liquid is especially corrosive or apt to prevent reliable action of the backflow prevention device, air gap separation shall be provided. These devices shall be tested by the water user at least once a year; or more often in those instances where successive inspections indicate repeated failure. The devices shall be repaired, overhauled or replaced whenever they are found to be defective. These tests must be performed by a qualified backflow prevention device tester and records of tests, repairs, and replacement shall be kept and made available to the Water Purveyor and the Health Department upon request.
Sewage pumps shall not have priming connections directly off any drinking water systems. No connections shall exist between the drinking water system and any other piping, equipment, or tank in any sewage treatment plant or sewage pumping station.
Where the circumstances are such that there is special danger to health by the backflow of sewage, as from sewers, toilets, hospital bedpans and the like, into a drinking water system, a dependable device or devices shall be installed to prevent such backflow.
The purpose of these regulations is not to transcend local plumbing regulations but only to deal with these extraordinary situations where sewage may be forced or drawn into the drinking water piping. These regulations do not attempt to eliminate at this time the hazards of backsiphonage through flushometer valves on all toilets, but deal with those situations where the likelihood of vacuum conditions in the drinking water system is definite and there is special danger to health. Devices suited to the purpose of avoiding backsiphonage from plumbing fixtures are roof tanks, barometric loops or separate pressure systems separately piped to supply such fixtures, recognized approved vacuum or siphon breaker and other backflow protective devices which have been proved by appropriate tests to be dependable for destroying the vacuum.
Inasmuch as many of serious hazards of this kind are due to water supply piping which is too small, thereby causing vacuum conditions when fixtures are flushed or water is drawn from the system in other ways, it is recommended that water supply piping that is too small be enlarged whenever possible.
Backflow protection by a suitable backflow prevention device shall be provided on each drinking water pier head outlet used for supplying vessels at piers or waterfronts. These assemblies must be located where they will prevent the return of any water from the vessel into the drinking water pipeline or into another adjacent vessel. This will prevent such practices as connecting the ship fire-pumping or sanitary pumping system with a dock hydrant and thereby pumping contaminated water into the drinking water system, and thence to adjacent vessels or back into the public mains.
Where the premises contain dual or multiple water systems and piping, the exposed portions of pipelines shall be painted, banded or marked at sufficient intervals to distinguish clearly which water is safe and which is not safe. All outlets from secondary or other potentially contaminated systems shall be posted as being contaminated and unsafe for drinking purposes. All outlets intended for drinking purposes shall be plainly marked to indicate that fact.
Water supervisor. The Health Department and the Water Purveyor shall be kept informed of the identity of the person responsible for the water piping on all premises concerned with these regulations. At each premise where it is necessary in the opinion of the Water Purveyor a water supervisor shall be designated. This water supervisor shall be responsible for the installation and use of pipelines and equipment and for the avoidance of cross-connections.
In the event of contamination or pollution of the drinking water system due to a cross-connection on the premises, the local health officer and Water Purveyor shall be promptly advised by the person responsible for the water system so that appropriate measures may be taken to overcome the contamination.