- What is
Cross-Connection Control and Backflow all about?
Water is ordinarily distributed in one direction: from the water
supplier to the consumer. However, it is possible, and not
all that uncommon for this to be changed by various hydraulic
conditions. The flow of water may be effectively reversed, flowing
from the consumer to the water supplier. This is called Backflow .
The water supplier is then faced with the problem of having water
introduced into the potable water distribution system from a source it
cannot control: the consumer. If this consumer happens to
have non-potable substances (those not
suitable for human consumption) on the premises, these substances could
find their way into the customer's water pipes when backflow
occurs. These substances could, in turn, get in to the water
distribution system. This causes contamination or pollution of the
water distribution system.
The physical connections between drinking water pipes and substances
which are not meant for consumption are called cross-connections. To
control these cross-connections and prevent backflow, a Backflow Preventer
must be installed at the point of the cross-connection.
These backflow preventers must be tested or inspected upon installation
to assure they are operating properly. Additionally, they must be
tested or inspected annually
to determine their continued capability to prevent backflow.
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- Who Needs
One? District's Policy on Backflow Devices. Installation
of an approved backflow prevention assembly is required at the service
connection to any premise where there is an auxiliary supply or system -
even if there is no connection or cross-connection. For example, anyone with an alternate source
of water such as a well, spring, stream, etc., or anyone with an irrigation system, or two
or more meters serving one parcel must have a backflow prevention device.
Commercial and professional buildings with fire sprinklers, lab equipment, boilers,
etc., are further examples of premises that require a backflow prevention device.
The State of California Administrative Code, Title 17 and Rule
11-16 of the Rules and Regulations of the Paradise Irrigation District,
require the owner of any premises on which protective devices are
installed to have certified annual inspections made of such devices for
their water tightness and reliability. The device shall be
serviced, overhauled, or replaced whenever found to be defective.
Certified records of such inspections and/or repairs are required to be
submitted to the District. You may engage any Backflow Prevention
Tester who is USC and AWWA certified to perform the test, or you may
have one of our certified employees perform the test.
However, PID will not be responsible for any repairs, re-testing, or any
plumbing problems that may occur on your premises due to the testing
procedures.
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- Potential
Hazards of not having a Backflow Prevention Device - Contamination or
pollution of a water system is usually brought about by a cross-connection to any systems
containing auxiliary water supplies which may be polluted or contaminated; irrigation
systems which may be polluted or contaminated with fertilizers, pesticides or other
objectionable materials. Thus, using a hose-attached sprayer for application of
pesticides, solvents, cleaning products, etc; flushing a car's cooling system with a
garden hose; or filling a swimming pool can all create situations where cross-connection
can occur. Without proper protection, devices as useful as your garden hose
have the potential to poison your home's water supply. In fact, over half of the
nation's cross-connections involve unprotected garden hoses!
Back to Top Types of Backflow Assemblies
Contact our office for assistance in determining what is suitable for your
application.
Double Check Valve Backflow Preventer
Used for Low Hazard Cross-Connections and
Continuous Pressure Applications
Example of use: Residential, Commercial, Industrial Supply Lines, Lawn Sprinklers,
Fire Sprinklers, Commercial Pools, etc.
Reduced Pressure Zone Backflow Preventer
Used for High Hazard Cross-Connection and Continuous
Pressure Applications
Example of use: Commercial Boilers, Hospital Equipment, Laboratories etc.
Pressure Vacuum Breaker Assembly
(Primarily for irrigation use)
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- Testing-PID
maintains records of backflow devices as part of its cross-connection
control program. Customers with backflow prevention devices
will receive annual notification by mail when backflow testing is
required. To have backflow testing done by PID, simply detach and
sign the indicated portion of the notification letter and return it to
PID, enclosing a payment of $40.00 for each device tested. Upon
receipt of payment, PID will perform the test. Test results will
only be sent out in the event that the device does not pass, and repair
and re-testing are requested. An additional charge of $40.00 will
be made for each device re-tested. If an independent Backflow
Prevention Tester is hired to perform the testing the certified test
results must be sent to PID upon completion of the test. Should
you have any questions about your backflow device, please contact our
office at (530) 877-4971. It takes about 15 minutes for the test
to be performed
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Cross-Connection
Control Terms
Back-siphonage:
A back-siphonage condition can occur whenever there is a lowered pressure
between the potable and non-potable supply piping. Such conditions typically occur
during periods of high demand in the public water main, lowering the supply pressure.
For instance during the demands imposed by fire fighting operations, or in the
event of a water main break, which suddenly and significantly lowers the city water
pressure below that of the non-potable system. This results in a partial vacuum
being drawn on the non-potable system, and siphons the pollutants or contaminants into the
potable water system through an unprotected cross connection, such as a hose bib or
hydronic system make-up connection. Back-siphonage may also occur when a high
velocity stream of water passes by a small pipe outlet, such as a residential service tap,
due to the "venturi" effect.
Back-pressure:
A back-pressure condition occurs whenever an elevated pressure exists between
the potable and non-potable source. These pressures can be imposed by the
installation of pumps which increase pressures above the city water supply pressure,
thereby forcing non-potable water in the opposite direction of normal flow into the
potable water line. The installation of boilers or other equipment which heat water,
causing thermal expansion and resulting in pressures in excess of the incoming water
pressure, also can force non-potable water into the potable piping system.
Pollutants:
A "pollutant" is any substance which may affect the color, taste or
odor of the potable water, but which does not pose a direct threat to human health through
exposure or consumption of the water. Pollutants may impose an objectionable odor or
appearance to the water, but do not in themselves pose a health threat, and therefore, are
considered to be a lesser hazard, when compared to contaminants.
Contaminant:
A "contaminant" is any substance which, when introduced into the potable water
system, constitutes a direct threat to life or health of a human, if the substance was
ingested through consumption, or if the substance came in contact with the skin. A
contaminant can therefore be a caustic chemical, a fluid containing bacteria or disease,
or any other substance which could threaten human health. Therefore, contaminants
compose the highest degree of hazard to the potable water system.
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- Cost
- The cost of a backflow prevention device for residential protection
can be anywhere from $100-$200.00 dollars plus the cost of having a
licensed plumber install it. Backflow devices for other applications may
be substantially more expensive.
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