We'd like to share some of the answers to questions
we've been asked:
BACKFLOW BASICS 101: Some
Commonly Asked Questions
What is a cross-connection?
Any permanent or temporary
connection between the potable water and any other non-potable fluid or
substance is a cross-connection. A feed line to a cooling tower, a
lawn sprinkler system or a hose dropped into a pesticide tank are some
Backflow is simply the reversal of the normal flow of the potable
water. It can be harmful or deadly if chemicals or bacteria are
the potable water through a cross-connection with a non-potable source.
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.
Backflow occur often?
Backflow is a
constant possibility in virtually any plumbing system, and cannot
generally be engineered out of a system
without the installation and
of appropriate backflow devices or measures. Backflow incidents most
often are caused when water pressure is lost temporarily, which allows back-siphonage
Backflow incidents dangerous?
incidents across the country often lead to property damage, injuries and
worst backflow incident on record, over 1500 persons became ill and 98
journals and magazines reveal
new cases every month.
Who Needs One?
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,
further examples of premises that require a backflow prevention device.
Each Municipality in each State, has Rules and Regulations
governing backflow protection requirements. Most 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 their respective Districts. You may engage any Backflow Prevention Tester
who is USC and AWWA certified to perform the test.
Is my company liable for backflow incidents?
owners who fail to maintain their plumbing systems up to code, or
fail to install backflow assemblies where needed
or to test these assemblies
annually are generally liable for backflow incidents on site, regardless
of the actual cause of the incident. Landlords who do not adequately monitor the activities of
tenants on site are generally responsible for damages or injuries
is the impact of the Backflow Codes?
Water purveyors have started cross-connection control
programs, and must mandate
the installation and annual testing of backflow devices at the user's
meter for system
protection, wherever an actual or a potential backflow hazard exists on
are my on-site backflow assemblies for?
assemblies are devices installed in your facilities at the point of
cross connection to prevent on-site backflow occurrences. It is these
devices that actually provide protection to your staff and/or customers, rather than the
assemblies at the
protect the city main lines. The plumbing code requires
that on site
assemblies be tested annually also.
do I need to test my backflow assemblies?
The state regulations and/or the Uniform Plumbing Code
require testing all assemblies annually. But regulations aside, keeping all of your
assemblies in good
condition not only reduces your legal liability exposure, it also lowers
your actual maintenance costs as
well. It's smart to catch problems
while they're minor, rather than wait until an emergency arises, such as when a device starts to
hundreds of gallons of water per minute out it's relief valve into an office or
room. Annually testing your devices is the only
way to guarantee that all internal
components of your device are working.
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!
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. Commercial - thousands of dollars
• Cross-Connection Control Terms
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
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.
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,
considered to be a lesser hazard, When compared to contaminants.
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
or any other substance which could threaten human health. Therefore, contaminants compose the
highest degree of hazard to the potable water system.
general information, or for an examination of your company's requirements,
Who Do I Call?
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