What is a cross-connection?
A cross-connection is an actual or potential connection between the safe drinking water (potable) supply and a source of contamination or pollution. Cross-connections must be properly protected or eliminated.
Liberty customers expect high quality water that is safe and pleasant to drink. Liberty invests millions of dollars into the system so that high quality potable water can continue to be delivered to our consumers. Our staff works diligently to protect the potable water from pollution or contamination, even when it’s flowing through the distribution system.
A cross-connection is an actual or potential connection between the safe drinking water (potable) supply and a source of contamination or pollution. Cross-connections must be properly protected or eliminated.
Backflow is the undesirable reversal of flow of water or mixtures of water and other liquids, gases, or other substances into the distribution pipes of the potable supply of water from any source or sources. When this happens the water system can become contaminated with pollutants that could be harmful to water users.
There are two conditions that contribute to backflow:
Any elevation of pressure in the downstream piping system (by pump, elevation of piping, steam pressure, air pressure, etc.) above the supply pressure at the point of consideration, which would cause or tend to cause a reversal of the normal direction of flow.
A form of backflow due to a reduction in system pressure, which causes a sub-atmospheric pressure to exist in the water system. When atmospheric pressure is greater than the potable water side, a reversal of flow can take place from the non-potable side.
There are many possible situations that can create backflow. The most important point is that without a properly functioning backflow prevention device, water can unexpectedly reverse in flow from a property or premise and draw with it any undesirable materials from the points of use into the drinking water system.
An example of cross-connection is a garden hose running while it is laying in a water source like a pool or other form of non-potable liquid. If the pressure drops in the distribution system, using a garden hose without backflow prevention can pollute or contaminate a water system from back-siphonage.
Anywhere there is a potential for contamination or pollution of the drinking water system, a backflow prevention device is required. Devices can be small and simple, such as an anti-siphon vacuum breaker (AVB) on a hose spigot, or large and complex, like a Double Check Detector Assembly (DCDA), which is an outgrowth of the double check valve and is primarily utilized in fire line installations.
Note: In Rio Rico and Sierra Vista, only the RP backflow device is required.
Reduced Pressure Principal (RPP) backflow prevention device.
There are other types of devices to protect the water distribution system or on-site potable system. The type of device to be installed to protect the potable water system is determined based on water use and backflow potential. Types of backflow prevention devices are listed below:
Federal and State law requires water suppliers to protect their water systems from contamination and pollution. Under the Arizona Department of Environmental Quality (ADEQ), all water purveyors must have a Cross-Connection Control Program.
As part of Liberty’s Cross-Connection Program, the Cross-Connection Control Specialist routinely conducts surveys of new and existing facilities to determine which type of backflow prevention is necessary to protect the water system.
Liberty must assure that the distribution system is protected from contamination and pollution from backflow. If backflow prevention is required at the water meter, these devices must be tested initially and annually to assure they are operating correctly. Tests and maintenance of backflow prevention devices must be conducted by AWWA Certified Testers.
Certified testers are responsible for performing accurate tests, and repairing or replacing devices that fail. Additionally, testers must report all repairs and test results to Liberty. After the testing is complete, the tester should give a copy of the test report to the customer and send the original report to Liberty and upload the results to BSI.
Plumbers, landscapers and other contractors are required to follow the latest publication of the Uniform Plumbing Code (UPC) regarding backflow and cross-connection prevention. Customers should contact state licensed contractors for modifications to their plumbing.
The backflow prevention device test only takes a few minutes. The test assures that each part of the device is operating correctly. If the device fails the first test, the tester must investigate the reasons for the failure and, if necessary, repairs must be made. Often, cleaning will correct the problem. To maintain proper protection, devices that fail the initial test must be repaired and re-tested within 15 days.
Customers that receive annual notices for testing and have questions regarding backflow should contact the Cross-Connections Specialist.
Any elevation of pressure in the downstream piping system (by pump, elevation of piping, steam pressure, air pressure, etc.) above the supply pressure at the point of consideration, which would cause or tend to cause a reversal of the normal direction of flow.
A form of backflow due to a reduction in system pressure, which causes a sub-atmospheric pressure to exist in the water system. When atmospheric pressure is greater than the potable water side, a reversal of flow can take place from the non-potable side.
An impairment of the quality of the water which creates an actual hazard to public health through poisoning or through the spread of disease by sewage, industrial fluids, waste, etc.
The water system begins with the source of water such as groundwater or surface water. Wells, pumps and treatment facilities are part of the water system which delivers water to the distribution system. The water distribution system consists of tanks and pipes which store and deliver treated water to customers.
Pollution is an impairment to the quality of the water to a degree which does not create a hazard to the public health but which does adversely and unreasonably affect aesthetic qualities.
Potable (POE-tuh-bull) water is water that does not contain objectionable pollution, contamination, minerals, or infective agents and is considered satisfactory for drinking and other domestic purposes.