Definitions.
AIR GAP
The unobstructed vertical distance through the free atmosphere
between the lowest opening from any pipe or faucet conveying water
or waste to a tank, plumbing fixture, receptor, or other assembly
and the flood level rim of the receptacle. These vertical, physical
separations must be at least twice the diameter of the water supply
outlet, but never less than one inch.
APPROVED
Accepted as meeting an applicable specification stated or
cited in this section and as suitable for the proposed use.
AUXILIARY WATER SUPPLY
Any water supply on or available to the premises other than
the City's approved public water supply system. These auxiliary supplies
may include water from another waterworks' public water supply system
or any natural source(s), such as a well, spring, river, stream, harbor,
and so forth; used waters; or industrial fluids. These waters may
be contaminated or polluted, or they may be objectionable and constitute
an unacceptable water source over which the City does not have sanitary
control.
BACKFLOW
The undesirable reversal of flow in a potable water distribution
system as a result of a cross-connection.
BACKPRESSURE
A pressure, higher than the public system supply pressure,
caused by a pump, elevated tank, boiler, or any other means that may
cause backflow.
BACKSIPHONAGE
Backflow caused by negative or reduced pressure in the public
water supply system.
CONTAMINATION
An impairment of a public water supply system by the introduction
or admission of any foreign substance that degrades the quality and
creates a health hazard.
CROSS-CONNECTION
A connection or potential connection between any part of
a public water supply system and any other environment containing
other substances in a manner that, under any circumstances would allow
such substances to enter the public water supply system. Other substances
may be gases, liquids, or solids, such as chemicals, waste products,
steam water from other sources (potable or nonpotable), or any matter
that may change the color or add odor to the water.
CROSS-CONNECTION CONTROL BY CONTAINMENT
The installation of an approved backflow-prevention assembly
at the water service connection to any customer's premises, where
it is physically and economically unfeasible to find and permanently
eliminate or control all actual or potential cross-connections within
the customer's water system; or it shall mean the installation of
an approved backflow-prevention assembly on the service line leading
to and supplying a portion of a customer's water system where there
are actual or potential cross-connections that cannot be effectively
eliminated or controlled at the point of the cross-connection.
CROSS-CONNECTION-CONTROLLED
A connection between a public water supply system and a nonpotable
system with an approved backflow-prevention assembly properly installed
and maintained so that it will continuously afford the protection
commensurate with the degree of hazard.
DEGREE OF HAZARD
Derived from an evaluation of the potential risk to public
health and the adverse effect of the hazard upon the public water
supply system.
(1)
HAZARD, HEALTHA cross-connection or potential cross-connection involving any substance that could, if introduced into the public water supply system, cause death or illness, spread disease, or have a high probability of causing such effects.
(2)
HAZARD, PLUMBINGA plumbing-type cross-connection in a customer's private plumbing system that has not been properly protected by an approved air gap or an approved backflow-prevention assembly.
(3)
HAZARD, NON-HEALTHA cross-connection or potential cross-connection involving any substance that generally would not be a health hazard, but would constitute a nuisance or be aesthetically objectionable if introduced into the public water supply system.
(4)
HAZARD, SYSTEMAn actual or potential threat of severe damage to the physical properties of the public water supply system or the customer's private plumbing system, or of a pollution or contamination that would have a protracted effect on the quality of the public potable system.
DOUBLE CHECK VALVE ASSEMBLY
The approved double check valve assembly consists of two
internally loaded check valves, either spring loaded or internally
weighted, installed as a unit between two tightly closing resilient-seated
shutoff valves and fittings with properly located resilient-seated
test valves. This assembly shall only be used to protect against a
non-health hazard (that is, a pollutant).
INDUSTRIAL-FLUIDS SYSTEM
Any system containing a fluid or solution that may be chemically,
biologically, or otherwise contaminated or polluted in a form or concentration,
such as would constitute a health, system, pollution, or plumbing
hazard, if introduced into an approved public water supply system.
This may include, but not be limited to, polluted or contaminated
waters; all types of process waters and used waters originating from
the public water supply system that may have deteriorated in sanitary
quality; chemicals in fluid form; plating acids and alkalies; circulating
cooling waters connected to an open cooling tower; and/or cooling
towers that are chemically or biologically treated or stabilized with
toxic substances; contaminated natural waters, such as wells, springs,
streams, rivers, bays, harbors, seas, irrigation canals or systems,
and so forth; oils, gases, glycerin, paraffins, caustic and acid solutions,
and other liquid and gaseous fluids used in industrial or other purposes
for firefighting purposes.
POLLUTION
The presence of any foreign substance in water that tends
to degrade its quality so as to constitute a non-health hazard or
impair the usefulness of the water.
REDUCED-PRESSURE BACKFLOW-PREVENTION ASSEMBLY
The approved reduced-pressure principle backflow-prevention
assembly consists of two independently acting approved check valves
together with a hydraulically operating, mechanically independent
pressure differential relief valve located between the check valves
and below the first check valve. These units are located between two
tightly closing resilient-seated shutoff valves as an assembly and
equipped with properly located resilient-seated test spigots.
SERVICE CONNECTION
The terminal end of a service connection from the public
water supply system, where the City loses jurisdiction and sanitary
control over the water at its point of delivery to the customer's
private plumbing 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 should be no unprotected takeoffs from the
service line ahead of any meter or backflow-prevention assembly located
at the point of delivery to the customer's water system. Service connection
shall also include water service connection from a fire hydrant and
all other temporary or emergency water service connections from the
public water supply system.
WATER, NONPOTABLE
Water that is not safe for human consumption or that is of
questionable quality.
WATER, POTABLE
Water that is safe for human consumption as set forth by
the Virginia Department of Health, Office of Drinking Water.
WATER, USED
Any water supplied by the City from a public water supply
system to a customer's private plumbing system after it has passed
through the point of delivery and is no longer under the sanitary
control of the City.