The protective device required shall depend on the degree of hazard as tabulated below:
(A) At the service connection to any premises where there is an auxiliary water supply handled in a separate piping system with no known cross- connection, the city water supply shall be protected by an approved double check valve assembly.
(B) At the service connection to any premises on which a substance that would be objectionable (but not necessarily hazardous to health), if introduced into the public water supply, is handled so as to constitute a cross-connection, the city water supply shall be protected by an approved double check valve assembly.
(C) At the service connection to 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 approved reduced pressure principle backflow prevention device. A double check valve assembly may be used in lieu of such device if local experience indicates that double check valves are reliably operated and if approved by the water purveyor and local health agency.
(D) 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, the public water supply shall be protected by an air- gap separation. The air-gap shall be located as close as practicable to the service cock and all piping between the service cock and receiving tank shall be entirely visible. If these conditions cannot reasonably be met, the public water supply shall be protected with an approved reduced pressure principle backflow prevention device.
(E) At the service connection to any sewage treatment plant or sewage pumping station, the city water supply shall be protected by an air-gap separation. The air gap shall be located as close as practicable to the service cock and all piping between the service cock and receiving tank shall be entirely visible. If these conditions cannot be reasonably met, the public water supply shall be protected with an approved reduced pressure principle backflow prevention device, providing this alterative is acceptable to both the water purveyor and local health agency. Final decision in this matter shall rest with the State Department of Public Health.
('61 Code, § 24.93) (Ord. 604, passed - - )