The purpose of this chapter is to:
A.
Protect the public water supply against actual or
potential cross-connections by isolating within the premise contamination
or pollution that may occur because of some undiscovered or unauthorized
cross-connection on the premise.
B.
Eliminate cross-connections or install approved backflow
preventers on existing cross-connections between drinking water systems
and other sources of water or process water used for any purpose whatsoever
which jeopardize the safety of the drinking water supply.
C.
Protect the drinking water supply within the premise
from hazards due to plumbing defects or cross-connections which may
endanger the drinking water supply available on the premise.
D.
Protect the public water supply through the establishment
of rules and regulations regarding installation and maintenance of
water lines.
A.
It is the intent of this chapter to recognize that
there are varying degrees of hazard and to apply the principle that
the degree of protection should be commensurate with the degree of
hazard.
B.
Experience in the United States has shown that it
is physically and economically infeasible to permanently eliminate
cross-connections within the consumer's premises. In-plant cross-connection
control programs, practiced almost universally, have been found to
be ineffective in protecting the public water system. Installations
that were originally made in accordance with approved plumbing codes
have been subsequently changed; air-gap separations have been either
eliminated or bypassed; vacuum breakers and other in-plant types of
backflow prevention devices have been either removed, improperly repaired
or allowed to become ineffective because of poor maintenance; and
cross-connections have been installed without benefit of inspection
and without backflow preventers.
A.
An effective backflow prevention device commensurate
with the degree of hazard should be incorporated in every meter and
installed at the service connection. This would reduce, if not completely
eliminate, the possibility of contamination of public water systems
due to in-plant cross-connections. Until a device of that type is
available, the public water system shall be protected at set forth
in the following regulations.
B.
No water service connection to any premises shall
be installed or maintained unless the public potable water supply
is protected as hereinafter set forth.
It is recognized that the control of cross-connections
requires cooperation between the Water Department, public health agencies
and the consumer. However, it is the intent of this chapter that the
Health Department shall have the responsibility for protecting the
potability of the consumer's water system. The Water Department shall
have the responsibility to prevent water from unapproved sources,
or any other substance, from entering the public water supply system.
It shall be its responsibility to inspect the water consumer's premises
to determine whether cross-connections or other hazards which would
endanger the public water system exist; evaluate its findings; and
to determine the degree of hazard. After determining the degree of
hazard, the Water Department has the further responsibility for ensuring
that an approved backflow prevention device, commensurate with the
degree of hazard, is installed, tested and maintained at the Water
Department's service connection. The installation, testing and maintenance
of an approved backflow prevention device at the service connection
will be considered as prima facie evidence that the Water Department
has fulfilled its responsibility.
In those cases where backflow protection at
the service connection is not specifically required, the Water Department
shall determine the hazard due to the possibility of future in-plant
changes that would nullify the protective steps that have been taken
by the Health Department and consumer and to do whatever is necessary
to ensure protection of the public water system.
As used in this chapter, unless the context
or subject matter otherwise requires, the following terms shall have
the meanings indicated:
A physical break between a supply pipe and a receiving vessel.
The air-gap shall be at least double the diameter of the supply pipe,
measured vertically above the top rim of the vessel, in no case less
than one inch.
A backflow prevention device (subject to back pressure) which
complies with specifications and test requirements as adopted by the
Research Foundation for Cross-Connection Control, University of Southern
California, and published in its USCEC Report Number 48-101, Definitions
and Specifications of Double Check Valve Assemblies and Reduced Pressure
Principle Backflow Prevention Devices.
Any water supply on or available to the premises other than
the approved public potable supply. These auxiliary waters may include
water from another public potable water supply or any natural source,
such as a well, spring, river, stream, etc., or used waters or industrial
fluids. They may be polluted or contaminated or they may be objectionable
and constitute an unacceptable water source over which the Water Department
does not have sanitary control.
The flow of water or other liquids, mixtures, gases or other
substances into the distributing pipes of a potable supply of water
from any source or sources other than its intended source. Backflow
may be evidenced under two conditions: pressure greater than atmospheric
(see "back pressure") and pressure that is sub-atmospheric (see "backsiphonage").
A device or means to prevent backflow of water or liquids
of questionable quality into the potable water system.
Backflow caused by a pump, elevated tank, boiler or other
vessel which could create pressures within the system greater than
supply pressures.
The flowing back of nonpotable water or other polluted or
contaminated liquids from a plumbing fixture or vessel into a potable
water supply due to a negative or subatmospheric water pipe.
A device which allows atmospheric pressure to enter a piping
system between the source of pollution and origin of the vacuum.
An impairment of the quality of the water by sewage or industrial
fluids or waste to a degree which creates an actual hazard to the
public health through poisoning or through the spread of disease.
Any real or potential unprotected connection between any
part of a water system used or intended to supply water for drinking
purposes and any source or system containing water or substance that
is not or cannot be approved as safe, wholesome and potable for human
consumption.
Shall be derived from the evaluation of a health, system,
plumbing or pollutional hazard.
An assembly of at least two independently acting approved
check valves, including tightly closing shut-off valves on each side
of the check valve assembly and suitable leak-detector drains, plus
connections available for testing the watertightness of each valve.
These devices for maintenance and testing must be installed in a location
where no part of the valve will be submerged.
An actual or potential threat of contamination or pollution
of a physical or toxic nature to the public potable water system to
such a degree or intensity that there would be a danger to health.
Plumbing-type cross-connections in a consumer's potable water system
that have not been properly protected by a vacuum breaker, air-gap
separation or other devices constitute a health hazard. They include,
but are not limited to, cross-connections to toilets, sinks, lavatories,
wash trays, domestic washing machines and lawn sprinkling systems.
Plumbing-type cross-connections can be located in many types of structures,
including homes, apartment houses, hotels and commercial and industrial
establishments.
Any fluid or solution which may be chemically, biologically
or otherwise contaminated or polluted in a form or concentration such
as would constitute a health, system, pollutional or plumbing hazard
if introduced into an approved water supply. This may include, but
not be limited to: polluted or contaminated used waters; all types
of process waters and used waters originating from the public potable
water system which may deteriorate in sanitary quality; chemicals
in fluid form; plating acids and alkalies; circulating cooling waters
connected to an open cooling tower and/or cooling waters that are
chemically or biologically treated or stabilized with toxic substances;
contaminated natural waters such as from wells, springs, streams,
rivers, irrigation canals or systems, etc.; oils, gases, glycerine,
paraffins, caustic and acid solutions and other liquid and gaseous
fluids used in industrial or other processes or for firefighting purposes.
An impairment of the quality of the water to a degree which
does not create an actual hazard to the public health but which does
adversely and unreasonably affect such waters for domestic use.
An actual or potential threat to the physical properties
of the water system or the potability of the public or the consumer's
potable water system which would constitute a nuisance or be aesthetically
objectionable or could cause damage to the system or its appurtenances,
but would not be dangerous to health.
A device incorporating two or more check valves and an automatically
operating differential relief valve located between the two checks,
two shutoff valves and equipped with necessary appurtenances for testing.
The device shall operate to maintain the pressure in the zone between
the two check valves less than the pressure on the public water supply
side of the device. At cessation of normal flow, the pressure between
check valves shall be less than the supply pressure. In case of leakage
of either check valve, the differential relief valve shall operate
to maintain this reduced pressure by discharging to the atmosphere.
When the inlet pressure is two pounds per square inch or less, the
relief valve shall open to the atmosphere, thereby providing an air-gap
in the device. To be approved, these devices must be readily accessible
for maintenance and testing and installed in a location where no part
of the valve will be submerged.
The terminal end of a service connection from the public
potable water system, i.e., where the Water Department loses jurisdiction
and sanitary control over the water at its point of delivery to the
consumer's water system. If a meter is installed at the end of the
service connection, then the service connection shall mean the downstream
end of the meter. There shall be no unprotected takeoffs from the
service line ahead of any meter or backflow prevention device located
at the point of delivery to the consumer's water system. It shall
also include water service from a fire hydrant or any other temporary
or regular water service connection.
Any water supplied by the Water Department from a public
potable water system to a consumer's water system after it has passed
through the point of delivery and is no longer under the control of
the City.
The consumer or a person on the premises appointed by him
charged with the responsibility of maintaining the consumer's water
system(s) on the property free from cross-connection and other sanitary
defects, as required by regulations and laws. A certified backflow
prevention device tester may not act as a Water Supervisor unless
he is a full time employee of the consumer having the day-to-day responsibility
for the installation and use of pipelines and equipment on the premises
and for the avoidance of cross-connections.
