The purpose of this chapter is to:
A. Protect the public potable water supply of Wayland from the possibility
of contamination or pollution by isolating within the customer's
internal distribution system or the customer's private water
system such contaminants or pollutants that could backflow into the
public water system;
B. Promote the elimination or control of existing cross-connections,
actual or potential, between the customer's in-plant potable
water system and nonpotable water systems, plumbing fixtures and industrial
piping systems; and
C. Provide for the maintenance of a continuing program of cross-connection
control that will systematically and effectively prevent the contamination
or pollution of all potable water systems.
The Water Superintendent shall be responsible for the protection
of the public potable water distribution system from contamination
or pollution due to the backflow of contaminants or pollutants through
the water service connection. If, in the judgment of said Water Superintendent,
an approved backflow-prevention assembly is required at the customer's
water service connection or within the customer's private water
system for the safety of the water system, the Water Superintendent
or his/her designated agent shall give notice, in writing, to said
customer to install such an approved backflow-prevention assembly
at a specific location on his/her premises. The customer shall immediately
install such approved assembly at his/her own expense, and failure,
refusal or inability on the part of the customer to install, have
tested and maintain said assembly shall constitute grounds for discontinuing
water service to the premises until such requirements have been satisfactorily
met.
As used in this chapter, the following terms shall have the
meanings indicated:
APPROVED
Accepted by the authority responsible as meeting an applicable
specification stated or cited in this chapter or as suitable for the
proposed use.
AUXILIARY WATER SUPPLY
Any water supply on or available to the premises other than
the purveyor's approved public water supply. These auxiliary
waters may include water from another purveyor's public potable
water supply or any natural source, 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 water purveyor
does not have sanitary control.
BACKFLOW
The undesirable reversal of flow in a potable water distribution
system as a result of a cross-connection.
BACKFLOW PREVENTER
An assembly or means designed to prevent backflow.
A.
AIR GAPThe 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, never less than one inch (25 millimeters).
B.
REDUCED-PRESSURE BACKFLOW-PREVENTION ASSEMBLYThe 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. These units are located between two tightly closing resilient-seated shutoff valves as an assembly and equipped with properly located resilient-seated test cocks.
C.
DOUBLE CHECK VALVE ASSEMBLYThe approved double check valve assembly consists of two internally loaded check valves, either spring loaded or internally weighted, installed as a unit between two properly located resilient-seated test cocks. This assembly shall only be used to protect against a non-health-hazard (that is, a pollutant).
BACKPRESSURE
A pressure, higher than the 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 supply
piping.
CONTAMINATION
An impairment of a potable water supply 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 potable water system and any other environment containing other
substances in a manner that under any circumstances would allow such
substances to enter the potable water 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 color or add odor to the water.
CROSS-CONNECTION CONTROL
A connection between a potable water system and a nonpotable
water 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.
CROSS-CONNECTION CONTROL BY CONTAMINANT
A.
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
B.
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.
HAZARD, DEGREE OF
The term is derived from an evaluation of the potential risk
to public health and the adverse effect of the hazard upon the potable
water system.
A.
HAZARD, HEALTHA cross-connection or potential cross-connection involving any substance that could, if introduced in the potable water supply, cause death or illness, spread disease or have a high probability of causing such effects.
B.
HAZARD, PLUMBINGA plumbing-type cross-connection in a consumer's potable water system that has not been properly protected by an approved air gap or an approved backflow-prevention assembly.
C.
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 a potable water supply.
D.
HAZARD, SYSTEMAn actual or potential threat of severe damage to the physical properties of the public potable water system or the consumer's potable water system or of a pollution or contamination that would have a protracted effect on the quality of the potable water in the system.
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 water supply. This may include, but
shall not be limited to, polluted or contaminated waters; all types
of process waters and used waters originating from the public potable
water system that may have deteriorated in sanitary quality; chemicals
in fluid form; plating acids and alkalis; circulating cooling waters
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,
paraffin and caustic and acid solutions; and other liquid and gaseous
fluids used in industrial or other purposes for fire-fighting 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.
SERVICE CONNECTION
The terminal end of a service connection from the public
potable water system, that is, where the water purveyor loses jurisdiction
and sanitary control over the water at its point of delivery to the
customer'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 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 potable water 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 described by
the public health authority having jurisdiction.
WATER SUPERINTENDENT
The Superintendent in charge of the Water Department of Wayland,
who is invested with the authority and responsibility for the implementation
of an effective cross-connection control program and for the enforcement
of the provisions of this chapter.
WATER, USED
Any water supplied by a water purveyor 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 sanitary
control of the water purveyor.
No water service connection to any premises shall be installed
or maintained by the water purveyor unless the water supply is protected
as required by state-provincial laws and regulations and this chapter.
Service of water to any premises shall be discontinued by the water
purveyor if a backflow-prevention assembly required by this chapter
is not installed, if the assembly has been removed or bypassed or
if an unprotected cross-connection exists on the premises. Service
will not be restored until such conditions or defects are corrected.
The customer's system should be open for inspection at
all reasonable times to authorized representatives of the Water Department
to determine whether cross-connections or other structural or sanitary
hazards, including violations of these regulations, exist. When such
a condition becomes known, the Water Superintendent shall deny or
immediately discontinue service to the premises by providing for a
physical break in the service line until the customer has corrected
the condition(s) in conformance with state-provincial and town statutes
relating to plumbing and water supplies and the regulations adopted
pursuant thereto.
An approved backflow-prevention assembly shall be installed
on each service line to a customer's water system at or near
the property line or immediately inside the building being served,
but in all cases before the first branch line leading off the service
line wherever the following conditions exist:
A. In the case of premises having an auxiliary water supply that is
not or may not be of safe bacteriological or chemical quality and
that is not acceptable as an additional source by the Water Superintendent,
the public water system shall be protected against backflow from the
premises by installing an approved backflow-prevention assembly in
the service line, appropriate to the degree of hazard.
B. In the case of premises on which any industrial fluids or any other
objectionable substances are handled in such a fashion as to create
an actual or potential hazard to the public water system, the public
system shall be protected against backflow from the premises by installing
an approved backflow-prevention assembly in the service line, appropriate
to the degree of hazard. This shall include the handling of process
waters and waters originating from the utility system that have been
subject to deterioration in quality.
C. In the case of premises having internal cross-connections that cannot
be permanently corrected and controlled or intricate plumbing and
piping arrangements or where entry to all portions of the premises
is not readily accessible for inspection purposes, making it impracticable
or impossible to ascertain whether or not dangerous cross-connections
exist, the public water system shall be protected against backflow
from the premises by installing an approved backflow-prevention assembly
in the service line.
All presently installed backflow-prevention assemblies that do not meet the requirements of this chapter but were approved assemblies for the purpose described herein at the time of installation and that have been properly maintained shall, except for the inspection and maintenance requirements under §
401-9, be excluded from the requirements of these rules so long as the Water Superintendent is assured that they will satisfactorily protect the utility system. Whenever the existing assembly is moved from the present location or requires more than minimum maintenance or when the Water Superintendent finds that the maintenance constitutes a hazard to health, the unit shall be replaced by an approved backflow-prevention assembly meeting the requirements of this chapter.