How Does a Backflow Preventer Work?
When you turn on a faucet in your home or shower, you can usually expect to get met with clean water. However, if your home’s drinkable water should come into contact with another water source, this can contaminate the supply. To stop this from happening, you may need a backflow preventer.
What Causes Backflow in a Property?
Backflow usually happens when the water flow in your home’s pipes changes direction. If this happens, your home’s drinking or clean water will encounter water exposed to chemicals and bacteria. Backflow tends to happen when various pressure levels exist between two points, which could result from high-pressure water flowing to low-pressure water. Usually, if you have backflow issues, this will happen due to back pressure or back-siphonage. Suppose you do not have a preventer installed. In that case, non-potable water can be introduced to your system, posing a hazard for whoever should use or drink the water. It’s important to consider things like this, or you may be unable to keep your family safe.
Should you Invest in a Preventor?
Backflow preventers are essentially devices in line with your home’s water pipes. They work by only allowing water to flow in one direction, preventing it from coming into contact with various other chemicals and bacteria. The purpose is to try and stop your drinking water from being contaminated due to backflow. Backflow preventers are more common in commercial settings, but that said, some houses can benefit. So that brings about the question, how do you know if you need to have one installed?
In short, the main reason for you to have one installed would be if you have a sprinkler system connected to your drinking water. Suppose you have an event which causes your home’s pressure to drop, or if you have a bust pipe. In this case, the difference in pressure can cause contaminants to run through the head of the sprinkler, introducing pesticides and fertilizer into your potable water.
There are some instances where a water break occurs in the line, meaning water is not actively pushed into your home and flows into the city line. This can result in the following contaminating your water lines and making you sick.
- Chlorine
- Pesticides
- Fertilizer
- Human waste
- Soap
- And more


The main benefit you can expect to take advantage of when you have a backflow preventer is that it prevents backflow from contaminating your home’s drinking supply. The idea of a backflow prevention device is to stop water if it does try and flow back into the main supply. According to Canadian law, municipal, provincial, and federal plumbing codes require backflow prevention if you have a potable water system. The best protection against any backflow is to have a well-designed and properly maintained air gap at the supplied fixture, which will give you the best protection against any backflow. In addition, an air gap is sometimes impractical and is also somewhat vulnerable to bypass arrangements. A mechanical backflow preventer can serve a similar purpose if you do not intend to use an air gap to safeguard against backflow. You can use many devices to stop backflow if it can withstand any back pressure.
According to Canadian regulations, there are six devices that you can use to try and prevent any backflow.
- Barometric loops
- Air gaps
- Pressure-reducing devices
- Double-check valves
- Double-check valves with atmospheric vents
- Pressure vacuum breakers and atmospheric Inspection and testing
Testing and inspections differ when you compare a non-mechanical option to a mechanical variant. Usually, with a non-mechanical variant, you must ensure that it is in place and has not been altered. With a mechanical option, you will have to inspect the moving parts, springs, seats, and more to ensure that they are not worn out. A test will also get done to ensure it works as it should, and CIFA recommends that you always have a qualified person test your system.
Want to find out more about backflow preventers and if you need one? Give us a call at 780-426-7878.