Cross Connections
and Backflow
Prevention
A cross connection is a point in a plumbing
system where the potable (drinking) water is connected to a non-potable
source. This is called backflow or when water flows in the opposite
intended direction within a water system. A partial list of common cross
connections found in water systems includes: clinics, laboratory
equipment, process equipment, floor drains, car washes, hose connections,
marinas, fire sprinkler systems and irrigation systems.
Why Be Concerned?
 Backflow
will occur when the water pressure in the public water supply is lost,
reduced, (back siphonage) or if the customer’s water pressure becomes
greater than the public supply (backpressure). Depending on the type of
cross connections that exist, contaminates can flow back into the
customer’s water system and eventually into the public water supply. In
addition to disease & illness, death can result when drinking water
becomes contaminated by chemicals such as lead, cyanide, caustics and
arsenic compounds. Pesticides and herbicides used widely in the home have
also caused death via cross connections. Identifying potential hazards
associated with cross connections, and eliminating or protection against
them is the concern of the Winterport Water District, the water industry
in general and public health agencies. Because almost all water systems
have cross connections, the water system personnel must
maintain a constant vigil for
their detection and elimination.
What causes backflow?
There are two types of backflow.
1 . Backsiphonage. A negative pressure that can be caused by water
main breaks, fire hydrant flushing or fire fighting. Backsiphonage can
draw all the water from a private water system. If this water is used for
boiler's, sprinkler systems etc. it could contain contaminated water.
2. Backpressure.
This is caused by the pressure in the private water system exceeding the
city's water system usually caused by a privately owned pump used to
increase pressure inside a single structure. This causes water to be
forced back into the city's system.
Types of Protection
All cross
connections must be eliminated or protected against by
approved methods or assemblies. Where cross connections cannot be
eliminated, backflow prevention assemblies must be installed. These must
be the brand and model approved by the State and must be tested after
installation and annually by a certified tester. The customer is
responsible for the initial and annual testing.
Containment or
Isolation?
A backflow device on the incoming line or
service is containment. The device is after the water meter, but before
any branches or connections to the service line. A backflow device
installed on a residential lawn sprinkler system is an example of an
isolation device. This device prevents lawn sprinkler water from getting
back into the home.
Program of
Implementation
The
Winterport Water District has implemented a cross connection control
program as required by State regulations. State regulations require the
District to identify cross connections and eliminate or protect by
approved methods or assemblies. The authority of this program extends to
all potential connections that could threaten the public water supply, but
not the general inspection and regulation of all consumer plumbing.
This is
done through two basic processes:
-
Through proper
installation and surveillance of backflow prevention assemblies on
service lines leading to premises where cross connections exist or are
likely to occur.
-
Through inspection and
regulation of plumbing within the premises to minimize the danger of
contamination of the water system within the premises or the public
water system itself.
To abide by
these requirements, all new and existing commercial businesses and
facilities will undergo a cross connection control inspection by the
Winterport Water District.
Potential Cross Connections
.
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FIXTURES WITH DIRECT CONNECTIONS
Air conditioning,
air washer
Air conditioning,
chilled water
Air conditioning,
condenser water
Air line
Aspirator,
laboratory
Aspirator, medical
Aspirator, weedicide
and fertilizer sprayer
Autoclave and
sterilizer
Auxiliary system,
industrial
Auxiliary system,
surface water
Auxiliary system,
unapproved well supply
Boiler system
Chemical feeder,
pot-type
Chlorinator
Coffee urn
Cooling system
Dishwasher
Fire standpipe or
sprinkler system
Fountain, ornamental
Hydraulic equipment
Laboratory equipment
Lubrication, pump
bearings
Photostat equipment
Plumber’s friend,
pneumatic
Pump, pneumatic
ejector
Pump, prime line
Pump, water operated
ejector
Sewer, sanitary
Sewer, storm
Swimming pool |
FIXTURES WITH SUBMERGED INLETS
Baptismal fount
Bathtub
Bedpan washer,
flushing rim
Bidet
Brine tank
Cooling tower
Cuspidor
Drinking fountain
Floor drain,
flushing rim
Garbage can washer
Ice maker
Laboratory sink,
serrated nozzle
Laundry machine
Lavatory
Lawn sprinkler
system
Photo laboratory
sink
Sewer flushing
manhole
Slop sink, flushing
rim
Slop sink, threaded
supply
Steam table
Urinal, siphon jet
blowout
Vegetable peeler
Water closet, flush
tank, ball cock
Water closet, flush
valve, siphon jet |
Inspection Procedures
If our
inspection of your facility finds cross connections, they will be listed
along with the approved methods or assemblies for eliminating or
protecting them. This information will be sent to the owner, along with a
compliance date. It will be the responsibility of the owners to see that
the listed cross connections are eliminated or protected. When the
compliance date is due, we will re-inspect the facility. The results of
such inspections will be sent to the owner.
REMEMBER:
When
making connections to potable water lines ALWAYS keep in mind that the
safety of others depends upon your providing adequate protections to the
water system by eliminating cross connections.
The
Cross Connection Program of the Winterport Water District derives its
authority from 22 MRSA ss 42 and 2612 and the Maine Dept. of Human
Services rules promulgated there under including the Cross Connection
Rules, l0l44A CMR Chapter 226, and the State Plumbing Code, l0l44A CMR
Chapter 238; and the Maine Public Utilities Commission 4l0 CMR Chapter 62
ss (4)(E).
Residential Backflow Prevention
and
Cross Connection Control Quick Guide
Cross Connection Control Program
of the Winterport Water District
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