A. 
Each service connection from a public water system for supplying water to premises having an auxiliary water supply shall be protected against backflow of water from the premises into the public water system, unless the auxiliary water supply is approved and monitored as an additional source by the water purveyor and is satisfactory to the public health agency having jurisdiction with regard to quality and safety.
B. 
Each service connection from a public water system for supplying water to premises, on which any substance is handled under pressure in such fashion as to permit entry into the water system, shall be protected against backflow of the water from the premises into the public system. This shall include the handling of process waters and waters originating from the public water supply system which may have been subject to deterioration in sanitary or chemical quality.
C. 
Each service connection from a public water system for supplying water to premises on which a substance of unusually toxic concentration or danger to health is handled in liquid form, even though it is not under pressure, shall be protected against backflow of the water from premises into the public system. Examples may include plating factories using cyanide and hospitals. This is not intended to apply to normal household installations.
D. 
Backflow prevention devices shall be installed on the service connection to any premises that have internal cross-connections, unless such cross-connections are abated to the satisfaction of the water purveyor.
E. 
All fires occurring and requiring fire-fighting apparatus to be connected to fire hydrants must use soft suction hose to make the connection.
F. 
It shall be the responsibility of the water user to provide and maintain these protective devices, and each one must be of a type and installation acceptable to the State Health Department.
The protective device required shall depend on the degree of hazard as indicated below:
A. 
At the service connection to any premises where there is an auxiliary water supply handled in a separate piping system with no cross-connection, the public water supply shall be protected by an approved backflow prevention device.
B. 
At the service connection on any premises on which there is an auxiliary water supply where cross-connections are known to exist which cannot be presently eliminated, the public water supply system shall be protected by an air-gap separation or an approved reduced pressure principle backflow prevention device.
C. 
At the service connection to any premises on which a substance that would be objectionable (but not hazardous to health if introduced into the public water supply) is handled so as to constitute a cross-connection, the public water supply shall be protected by an approved double check valve assembly.
D. 
At the service connection to any premises on which a substance of unusual toxic concentration or danger to health is or may be handled, but not under pressure, the public water supply shall be protected by an air-gap separation or an approved reduced pressure principle backflow prevention device. This device shall be located as close as practicable to the water meter, and all piping between the water meter and receiving tanks shall be entirely visible.
E. 
At the service connection to any premises on which any material dangerous to health, or toxic substance in toxic concentration, is or may be handled under pressure, the public water supply shall be protected by an air-gap separation. The air-gap shall be located as close as practicable to the water meter, and all piping between the water meter and receiving tanks shall be entirely visible. If these conditions cannot reasonably be met, the public water supply shall be protected with a reduced pressure principle backflow prevention device, providing the alternative is acceptable to the water purveyor.
F. 
At the service connection to any sewage treatment plant or sewage pumping station, the public water supply shall be protected with an approved reduced pressure principle backflow prevention device.
G. 
At the service connection to any premises not covered by Subsections A through F above, the public water supply shall be protected with an approved single check valve assembly.
A. 
It shall be the duty of the water user on any premises on account of which backflow protective devices are installed, to have competent inspections made at least once a year, or more often in those instances where successive inspections indicate repeated failure. These devices shall be repaired, overhauled or replaced at the expense of the water user whenever they are found to be defective. These tests shall be performed by a qualified backflow prevention device tester, and all test results will be provided to the water purveyor within 72 hours after the test is made.
B. 
Records of such test, repairs, and overhaul shall also be kept and made available to the water purveyor and the local Health Department upon request.