The last thing you want happening in your home is for you and your occupants using or ingesting contaminated water. Most times we do take clean and fresh water for granted until something goes really wrong. An example of something that could go wrong is when your plumbing system experiences a backflow. In this article we will discuss what that is in detail and why you will need to get in touch with your local plumber for them to administer the appropriate backflow testing procedure.

What is backflow?

Backflow refers to a plumbing issue where the waterflow moves in reverse in your plumbing system. Instead of water flowing in one direction(clean water enters, dirty water exists) ,things like drop in pressure because of freezing and bursting, a high increase in water usage of the water supply, improper installation of your pipes or water leaks could cause backflow leading to contaminated water from a ground source or storage flowing into the system.

Try and imagine the water you flush down the toilet finding its way to your home’s clean water supply. That’s why it’s important that the pressure in a water system is maintained to lower the risk of water flowing backwards into the water system. In case this were to happen, it’s important to note that the water is not drinkable and you should call your local plumber for inspection.

Do You Need A Backflow Prevention Device?

A backflow prevention device is a valve that prevents the reverse of waterflow from a polluted water source entering your drinking water supply system. Once your property is assessed by a professional plumber and they come to the conclusion that your property is a high or medium hazarders risk for backflow, then you will need this device. A property may have a backflow prevention device if it has;

  • An irrigation system
  • Water outlets close to pollutants or chemicals
  • Vehicle or bin wash down bays

If you do fall down in any of these groups or you suspect that you may be experiencing a backflow, you should then consider installing the device as soon as possible. These devices must be located at the water meter. Backflow prevention devices are available in three hazard ratings identified by AS/NZS 3500; high, medium and low. A high rating is extremely hazarders as it can cause death whereas a low rating will not endanger your health or cause any injuries but will be a nuisance. A qualified plumber will assess the hazard rating and assist you in determining the device your property needs. 

The Main Types Of Backflow Devices

Depending on the cause of the backflow issue and your water system, one of the following will be installed in your property.

Double Check Valve Assembly (DCVA)

This device has two spring loaded independently operating check valves and an outlet shut off valve.They can protect against back siphonage and back pressure.DCVA are designed for use only in low hazard scenarios.

Spill Resistant Vacuum Breakers (SRVB)

Spill-resistant vacuum breakers protect against backsiphonage but not against backpressure. They keep water from spilling out of the air inlet when the assembly becomes pressurized.

Pressure Vacuum Breakers (PVB)

This device is a common one as it is economical to purchase and use plus it’s easy to maintain and repair. It consists of different parts such as test valves, outlet shutoff valve, an inlet shutoff valve etc. The PVB has an air inlet valve that opens when the internal system pressure is higher than the external pressure preventing backsiphonage. The downside of PVB is that  they are not suitable to protect against back pressure. They can be used in both low and high hazard cases.

Reduced Pressure Principle Backflow Assembly

This device is considered as one of the safest and most reliable backflow preventers in the market not to mention expensive and difficult to install and maintain too. They can protect against chemigation backflow plus back siphonage and backpressure and can be used in both low-hazard and high-hazard cases.

Maintaining Your Backflow Prevention Device

Just like any other device, maintenance is important in order to ensure it works properly. Your plumber will check your device for any signs of malfunctioning then  test it to see if it is working as it should. After that the plumber will submit the test to the council. If the device did not pass the test, your certified backflow plumber will complete any required maintenance then the device will be retested and resubmitted.

Can You Do A Backflow Test On Your Own?

It’s important that backflow testing is done by professionals for accuracy purposes. Though there are potential signs of backflow that you can identify with your own eyes such as dirty or discolored water, strange smelling water or sediment on water. If you spot any of these signs, ensure to call your local plumber to professionally test your system.