WHAT IS A CROSS CONNECTION?
A cross-connection is a point in a plumbing system
where it is possible for a nonpotable substance to come into contact
with the potable drinking water supply. Common examples of
cross-connections include a garden hose submerged in a pesticide
mixture, a piped connection providing potable feed water to an
industrial process, such as a cooling tower, or a submerged outlet of
an irrigation system. Connections to firefighting equipment are other
very common cross-connections. Most cross-connections occur beyond
the customer service connection, within residential, commercial,
institutional or industrial plumbing systems. Identifying
cross-connections can be challenging because many distribution
systems are expanding to serve new customers and changing to
accommodate customer needs. Further, temporary and permanent cross
connections can be created in existing facilities without the
knowledge of the water system managers and operators.
WHAT IS BACKFLOW?
Backflow is any unwanted flow of used or
nonpotable water, or other substances from any domestic, industrial,
or institutional piping system back into the potable water
distribution system. The direction of flow under these conditions is
opposite to that of normal flow and is caused by either backsiphonage
backflow caused by a negative pressure (vacuum or partial vacuum) in
the supply piping. Backsiphonage occurs when system pressure is
reduced below atmospheric pressure. The effect is similar to sipping
water through a straw.
backflow caused by pressure in the customer's plumbing being greater
than the pressure in the water supply piping. The higher pressure in
the customer's plumbing may be from a booster pump, heating boiler,
Outside water taps and garden hoses tend to be
the most common sources of cross connection contamination at home.
The garden hose creates a hazard when submerged in a swimming pool or
when attached to a chemical sprayer for weed control. Garden hoses
that are left lying on the ground may be contaminated by fertilizers,
cesspools, or garden chemicals.
The Raynham Center Water District is continuously
jeopardized by cross connections unless appropriate valves, known as
backflow prevention devices, are installed and maintained. We
continually survey all industrial, commercial and institutional
facilities in our district to make sure all potential cross
connections have been identified and eliminated or properly protected
by a backflow prevention device. We also inspect and test each
backflow preventer to make sure that it is providing maximum
Please call this office at (508) 824-0020 should
you have any questions regarding cross connections and backflow.
For additional information please see the
following web sites:
Massachusetts Department of Environmental
Protection Cross Connection Regulations:
CROSS CONNECTION CONTROL
REDUCED PRESSURE BACKFLOW
PREVENTERS AND DOUBLE CHECK VALVE ASSEMBLIES TESTING AND REPAIR
In accordance with Drinking Water Regulations of
MASS 310 CMR 22.22 Sec. 13 (D), all installations of reduced pressure
backflow preventer assemblies shall be tested semi-annually by the supplier
of water. In addition, double check valve assemblies shall be tested
annually by the supplier of water. All tests must be conducted by a
certified Backflow Prevention Device tester in accordance with the
regulated test procedures. The result of these tests must be recorded
on the Standard Inspection and Maintenance Report Form. This form
must be completely filled out (including the cross connection ID#
from the DEP permit), signed and dated by the owner and the certified
tester. All copies of the Inspection and Maintenance Report Forms
shall be maintained by the owner. The owner or owner's agent must
maintain on the premises a spare parts kit and any special tools
required for removal and reassembling of devices which are to be
tested. The presence of these materials must be recorded on the
Inspection and Maintenance Report Form. Devices failing a test
or found defective shall be overhauled, repaired or replaced by a
plumber or a mechanical fire sprinkler contractor. They must be
licensed by the Commonwealth of Massachusetts and re-inspected within
two weeks of the initial inspection date.
Thank you for your cooperation in protecting the Raynham
Center Water District’s water supply.
If you desire any additional
information, please call us at (508) 824-0020.