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 cross-connection, the public water supply shall be protected by
an approved double-check-valve assembly.
B. At the service connection on any premises on which
there is an auxiliary water supply where cross-connections are known
to exist or where it is unknown if cross-connections exist, 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 doublecheck-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 an approved reduced pressure-principle backflow
prevention device, provided that the alternative is acceptable to
the water district.
F. At the service connection to any sewage treatment
plant or sewage pumping station, 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 be reasonably met, the public water supply shall
be protected with an approved reduced-pressure-principle backflow
prevention device.
G. If an approved single-check-valve assembly is not already installed at the service connection to any premises not covered by Subsections
A through
F above, then the public water supply shall be protected by the installation of an approved single-check-valve assembly at the same time a new or replacement meter is installed. It is the personal responsibility of the property owner to provide the device and see that it is installed.