What is a Backflow Test all about and why are Backflow Preventers important?
Clean Water: We drink it, cook with it, bathe in it, and participate in many activities using it. We enjoy the low cost and convenience of water flowing from our taps. But do we understand that the water we take for granted may pose a serious threat to our health if not properly managed?
Water systems are designed to deliver water from the treatment facility to the end user. The end user (or water customer) may be a home, an apartment building, a farm, an office high-rise, a park, a heavy industrial building or any number of other facilities.
Water providers take great care to insure the quality of the water they deliver, and to protect that water against the possibility of contamination or pollution. However, water providers have no control over what happens to the water in the end user’s facility. One of the great risks to our public and personal health occurs just outside our door: at the connection between the water supplier’s system and the end user’s system–the water meter.
HOW CAN THE WATER METER POSE A THREAT TO PUBLIC HEALTH?
Delivery systems will have pressure fluctuations, which may result in water flowing in the reverse of its normal direction. This reversal is called backflow. Backflow can cause substances other than water to enter the safe drinking water supply. These unwanted substances may then be delivered to other users of the water system (read: you and me). So in order to protect against contamination or pollution entering the public water system, backflow prevention assemblies are required to be installed and properly maintained.
There are two types of backflow: backsiphonage and backpressure. Back-siphonage is when the delivery pressure in the supply system drops. This pressure drop pulls the water from the end user back into the delivery system. For example, backsiphonage might occur when an underground water line breaks, or during the fighting of a fire. Water is “pulled” to the location of greatest use or the point of escape. Back-pressure is when the water pressure on the customer/end user’s side exceeds the pressure in the supply system. This high pressure “pushes” the water and anything in the end user’s system back into the public delivery system. This potential exists when a water supply line is connected directly to items such as pumps, boilers, chillers, dip tanks and tall buildings.
When either type of backflow occurs, pollutants and/or contaminants can be sent back into the distribution system from the end users property and will be available for delivery to the public when the next tap is opened requesting water. Federal and state laws require water suppliers to protect their water delivery systems from potential contamination and pollution. Backflow assemblies are used to provide a separation between the delivery systems and end user. Also, water customers may use backflow assemblies internally to protect themselves from known hazards within their own properties.
Backflow assemblies are mechanical devices with specific design requirements. Most backflow assemblies are submitted by their manufacturer to the Foundation for Cross-Connection Control and Hydraulic Research at the University of Southern California for laboratory and field testing. The Foundation’s approval process uses stringent specifications. Assemblies which successfully pass these tests are granted Approval by the Foundation. In the State of California, this approval is required in order for a backflow assembly to be used in the field.
Once installed, backflow assemblies must be field tested at least once each year to ensure they are working properly. When a field test determines that a device is not working properly, the assembly must be repaired and retested. Field testing must be performed by a certified backflow prevention assembly tester, using an approved and properly calibrated test gauge.
A certified backflow tester is someone who has successfully completed a course of instruction in backflow prevention assemblies which includes theory, design, performance, testing, and maintenance. Upon successful course completion which includes both written and performance examinations, the backflow tester certification is issued. Most certifications last for 2-3 years depending on the issuing agency. Prior to certificate expiration, the tester must again successfully complete both written and performance examinations in order to keep their certification active.
Providing a clean and safe water delivery system free from objectionable impurities requires the cooperation of water providers, water customers/end users and certified backflow prevention assembly testers. Please join with us in helping to protect our drinking water system and keeping safe water flowing to our taps.