Cross Connection Control & Backflow Prevention
The Cross Connection and Backflow Prevention Program of the Belfast Water
District is designed to regulate, control, and prevent the contamination of your
drinking water by the backflow of water or other liquids, mixtures or substances
into the distribution pipes of the Belfast water supply system from a source or
sources other than its intended source.
Since it is the responsibility of a public water
supply to provide water, which is safe to consume, and since active,
unprotected, or inadequately protected cross-connections provide a real and
present threat to the safety of the water being consumed we have developed the
following program to protect your drinking water.
Backflow means the reversal of water flow from its normal or intended direction
of flow. It is possible for the flow to be reversed, known as backsiphonage and
flow from the customerís plumbing system back into the public water distribution
system. If cross-connections exist within the userís plumbing system when
backflow occurs then it is possible to contaminate the public water system.
A cross-connection occurs when a drinking water supply pipe connects to a
non-drinking water supply source or pipe. An example of this is a connection
with a residential home. For example, if you have a hose that has a submerged
end in a kiddie pool or a carwash bucket, this is a cross-connection.
Backsiphonage may occur when the water pressure within the distribution system
falls below that of the plumbing system it is supplying. The loss of pressure
can be caused by a broken water main, or a fire nearby where the fire department
is using large quantities of water. Any building near the break or the fire
hydrant being used will experience a lowering of the water pressure.
Where backflow occurs and cross-connections are present you have all the
necessary elements for contamination of the plumbing system and subsequently
contamination of the public water system.
For example, suppose a automatic lawn sprinkler system is spraying a lawn when
all of a sudden a backsiphonage occurs due to a fire truck pumping water or
water rushing from a broken main. The resulting backflow from the lawn sprinkler
system will flow into the plumbing system and then into the water distribution
system. As the water backflows it can suck contamination into the lines through
the sprinkler heads, such as insects, pesticides, herbicides, fungicides,
fertilizers, worms, and other contaminants. Once in the distribution lines the
contamination could go anywhere in the public water system.
To prevent backflow from non-potable sources into our public water system check
valves or backflow prevention devices installed at the site of the
cross-connection can protect the plumbing system from contamination. Placed just
downstream of a water meter to an establishment, they can protect the public
water system from any contamination that may occur within the entire
establishmentís plumbing system.