What is a Backflow Preventer?
A backflow preventer is a device that is installed on water pipes. Backflow preventers allow water to flow in one direction but not in the opposite direction. The sole job is to make sure your drinking water isn’t contaminated due to backflow.
What is Backflow?
Backflow is when water enters your home from the main water supply line. It should only ever go in one direction. Due to pressure changes in the pipes, water can flow backwards. This causes it to seep back into the main water supply line.
When pressure is lost during these events, water can no longer be pushed forward into your home and will flow back into the city water lines. This can cause contamination in public water. Things that can contaminate your water are fertilizers/pesticides, human waste, chlorine, and soap.
Backflow occurs in cross-connections, like dishwashers, reverse osmosis devices, and between potable and nonpotable water lines.
Some Key Terms
There are a few key terms you may need to know when talking about backflow preventers. Back pressure results from waste water systems having greater pressure than the incoming fresh water supply. Problems in the sewer line can cause the pressure to increase and lead to back pressure.
Back siphonage is caused by negative pressure in the supply system usually by an unexpected pressure decrease. This can cause water from the sewer line to be pulled into the clean water line. This commonly happens when there are breaks or repairs being done on the water main.
Backflow testing can be required for businesses yearly and some states even require it for residential homes. When testing, plumbers will shut off your water and use gate and relief valves to check for leaks, unwanted movement.
What a Backflow Preventer Does
These backflow preventers do exactly what they say they do, and prevent backflow from getting in your water. They are installed onto a pipe that only allows water to flow in one way. It is a one way gate that allows water from the city’s public water supply to flow into your home’s piping.
Some cities require a backflow system to be installed if you have an irrigation system or a well. However, even if it is not required by law, it is still a good idea to have.
Types of Backflow Prevention Devices
The first type are called Air Gap Preventers. They are mainly used in sinks to prevent debris from entering drinking water or a dishwasher. In these types of devices there is a literal air gap between the water outlet and flood level of the dishwasher. These tend to be inexpensive and come in a variety of materials.
Air gap preventers eliminate contamination risk by separating the hose that runs dirty water and the hose that runs to the drain. They never intersect and contamination is very unlikely. Dual inlet air gaps are another version or air gap preventers. They can connect two dishwashers to one drain line or drain a dishwasher and a water filtration system.
Vacuum breakers are the second type of backflow prevention systems. Atmospheric Vacuum Breakers, or AVB, prevent backflow in the hose, faucet and spigot applications. They contain a check valve that opens an air vent when the system loses pressure. This process prevents back siphonage from occurring while the pressure is lost in the system. They have to be installed at least 6 inches above the ground to be effective.
Check valves are another type of backflow prevention systems. They ensure that the water flows in one direction and one direction only. Check valve systems open and shut based on the pressure on both sides of the valve. Check valves can be installed at the service entrance or at individual water outlets. These systems are designed for continuous pressure systems. They can be installed either horizontally or vertically; the others must be installed in orientation to the other.
Final Thoughts
Backflow Prevention Systems are sometimes required by law depending on where you get your water. However, even if you do not need them they are great to have in case something goes wrong. They are great at preventing contaminated water from coming into your clean water supply.
Call 1-Tom-Plumber
Don’t hesitate to contact or call us at 1-Tom-Plumber (1-866-758-6237). We will immediately handle any emergency plumbing, drain cleaning and drain clearing, and water damage problem, including excavation of underground water lines and sewer main lines.
