In standard backflow testing procedures, a certified backflow testing technician connects a test kit to the test ports on each backflow prevention device at the location to ensure the devices are functioning normally. Any backflow prevention devices that fail the testing procedure must be immediately repaired or replaced to avoid contaminating the rest of the water supply.
Backflow is the plumbing term that refers to undesired mixing that occurs when water inside a plumbing system travels in the wrong direction. Backflow becomes dangerous when used water from dishwashers, toilets and other contaminated sources flows back into buildings or the public water supply and mixes with clean water that people may consume.
Plumbing professionals install backflow prevention devices at all locations in a plumbing system where backflow is likely. A backflow prevention device typically consists of two mechanically linked check valves. When flow reverses direction, the valves snap shut, preventing potentially hazardous water from contaminating the system.
Eventually, most backflow prevention devices encounter problems that prevent them from functioning. The devices become dirty, clogged and occasionally seriously damaged. For dirty and clogged backflow prevention devices, the repair is fairly easy and involves disassembling and cleaning the device. Devices that have minor damage, like worn seals or brittle o-rings are also relatively easy and inexpensive to repair. Serious damage like cracked or shattered parts usually requires replacing all or part of the device.