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.