What is a backflow prevention
program? A mutual effort between water
companies, property owners and certified testers to
educate the public about backflow prevention
requirements. These requirements ensure that established
guidelines are followed to protect the public drinking
are we protecting the public supply from? How?
Our goal is to protect the drinking water supply from
pollutants or contamination. We do this by keeping water
that has already entered a facility from flowing back
into the public water system. Backflow prevention
assemblies are the devices used for this purpose.
What is the difference
between pollution and contamination?
Pollution of the water supply does not constitute an
actual health hazard, but the water may taste, smell, or
look objectionable. Contamination of the water supply
constitutes an actual health hazard, with the consumer
being subjected to potentially harmful water borne
disease or chemicals.
What causes water to flow
backward? Two things: backsiphonage and
What is backsiphonage?
Backsiphonage is created when there is a sudden drop in
water pressure in water mains due to breaks or nearby
What is backpressure?
The reversal of normal flow due to downstream pressure
being greater than supply pressure.
What causes backpressure?
Heating systems, elevated tanks, and
pressure producing systems can create pressure in the
customer's plumbing which exceeds the supply pressure.
An example would be a boiler operating at 100-150 lbs.
pressure (as in a commercial system).
Since a city's
water pressure is usually about 60 lbs. and water flows
in the direction of least resistance, a back pressure
would be created. The contaminated boiler water could
flow into the drinking water supply.
What is a backflow
prevention assembly? What is its purpose?
Where should it be installed? A backflow
prevention assembly is a testable device which uses
spring loaded check valves to prevent polluted or
contaminated water from flowing backwards. Some
assemblies eliminate backflow by discharging used water
to the ground. Assemblies installed as secondary
protection shall be located as close as possible to the
water meter or property line.
Why can't I just use check
valves as a backflow prevention assembly?
A check valve is not equipped with test connections to
assure that the valve is preventing backflow. That's why
only approved assemblies are allowed.
What is an approved assembly?
Any type of backflow prevention
assembly or method approved by the Arizona Department of
Environmental Quality (ADEQ).
anybody test backflow prevention assemblies in Arizona?
No, only people certified through an agency approved by
ADEQ can test backflow devices. A copy of his/her
certification must be on file with the Backflow
Who is a
certified tester? Any person trained to
test a backflow prevention assembly. This person must
pass a written and practical examination and have the
certificate described above.
Arizona Backflow Certification has certified testers!
Is it necessary for every water
customer to install an assembly? No.
State regulation exempt most single family homes used solely
for residential purposes from assembly requirements. All
other service connections need to be inspected to
determine the type of water use and whether an assembly
is required. The state however leaves it up to the local water
company to make the final determination in regards to
protecting their clean water supply.
If my building
was recently modified to meet city code requirements by
installing backflow preventers internally, do I still
need them at the service connection?
Even though plumbing code provisions may be rigidly
enforced on new installations, experience has shown that
"on-site" modifications and alterations of private
plumbing are common. Possible hazards to the public
water supply can be created due to backflow from private
plumbing. These hazards may be caused by a submerged
hose or a complex mechanical failure. In some cases, the
only practical way to assure protection is to install a
backflow preventer at the point of service delivery.
That way, regardless of what happens inside the
customer's property or what changes were made to private
plumbing, the public water supply is protected.
Where do I get a permit to install
a backflow prevention assembly? Permits
are issued by the city's Development Services
Department. If the service is for a fire sprinkler
system, an additional permit is required from the Fire
after I install the assembly?
It is your responsibility to have
the assembly tested when it is installed and each year
thereafter. A copy of the test
report showing that the assembly passed is to be
forwarded to the Backflow Prevention Unit. The city code
requires that test records be kept for three years.
What is an assembly test report
and where can I get one? A special
report form approved by the city used by certified
testers to log test results. The tester (Arizona
Backflow Certification) you hire will supply
the report form.