Protection of the system is required as set
forth in the following subsections:
A. Auxiliary water supply. 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 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. Substance under pressure. Each service connection
from a public water system for supplying water to the 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. Substance of unusual toxic concentration. Each service
connection from a public water system for supplying water to premises
on which a substance of unusual 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 are plating factories using cyanide and hospitals.
This is not intended to apply to normal household installations.
D. Internal cross-connections.
(1) 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.
(2) It shall be the responsibility of the water user to
provide and maintain these protective devices, and each one must be
of a type acceptable to the State Health Department.
The protective device required shall depend
on the degree of hazard as tabulated below:
A. Double check valve assembly. 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. Air-gap separation. 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. Objectionable substances. At the service connection
to any premises on which a substance that would be objectionable (but
not hazardous to health if introduced into the 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. Unusual toxic concentration. 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. Substance under pressure. 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 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 purveyor.
F. Sewage treatment plant or pumping station. 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. Other service connections. 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.