Backflow is hazardous condition in a plumbing system where non-potable water is siphoned into the drinking water supply. To prevent backflow a plumbing system must be designed properly and have backflow prevention devices installed. Here are examples of backflow prevention devices found in homes.
Atmospheric Vacuum Breaker (AVB)
Back-siphonage occurs when the system pressure drops, thereby forcing the pressure to become high to make up for the difference. When the pressure in the potable water system drops, it is possible that non-potable outflow can backflow into the system. This is where AVB is used to prevent the process of back-siphonage. AVBs comprise of an air inlet port, a check seat, and an air inlet valve.
Double Check Valves
These valves are designed to prevent backflow from two sources. They are typically installed in a series, with one valve installed upstream and one installed downstream. The valves work by allowing water to flow in one direction, while preventing backflow in the other direction.
Pressure Vacuum Breaker Valves (PVBs) – These valves are designed to prevent backflow from a pressurized water system. They work by allowing air to enter the system when the pressure differential rises, preventing backflow.
What is the difference between a backwater valve and a backflow preventer?
A backwater valve is a kind of prevention device used in plumbing systems to prevent sewage water from flooding the bathroom or basement. Backwater valves are installed at the lowest point of the sewage line. Backflow preventers, on the other hand, are mechanical devices used to prevent backflow of contaminated or polluted water from entering the water main. They are installed at the end of a pipe, typically at the point where the water enters the main supply line. Backflow preventers are required in regions where there is a risk for contaminants entering the public water supply.
Should you install backflow prevention devices in your home?
While not all municipalities in Colorado require backflow prevention devices in residential plumbing systems, we recommend that all homes have backflow devices installed, particularly homes with private wells. It’s relatively inexpensive to add the devices to your plumbing system and can help ensure that your drinking water is safe from contamination.
