Your irrigation system is the key to keeping a healthy landscape year-round, but they do require care, especially during installation. A backflow preventer is one of the most important components of any irrigation system. 

Here we explain the concept of backflow and why a simple tool to prevent it may help save you a headache in the future.

What is backflow?

In most areas, the irrigation system uses the same water supply as the house or main building. Backflow occurs when water moves the wrong direction from the irrigation system and back into the water supply.

The cause of backflow is simply the way water behaves. Water wants to go from an area of high pressure to an area of lower pressure, and this is exactly what it does.

So the issue occurs when the water pressure in the system is too high compared to the water supply. When this happens, the water looks to go where there is lower pressure – in this case, back to the water supply.

There are a number of reasons this could happen, including:

  • Line breaks
  • Frozen pipes
  • Any sudden reduction in water pressure to the supply line
  • A large amount of water being used at once, such as an open fire hydrant nearby
  • A sprinkler system that is not properly installed

Backflow may not be as common as a broken sprinkler head, but it can be a much larger issue.

The main issue with backflow has to do with contamination. Most sprinkler systems are set up along potable municipal water supply lines.

The water from the irrigation system may be contaminated with fertilizer, dirt, germs, and pesticides. Allowing water to flow back into the supply line contaminates the water, and may make it unsafe to use or consume.

If backflow occurs in your house, this can mean you are showering, brushing your teeth, or doing the dishes with contaminated water containing pesticides and fertilizer. Obviously it is best to avoid this however possible.

Because of the chance for contamination, many areas now require backflow preventers to be installed on every irrigation system.

What does a backflow preventer do?

Backflow preventers are relatively simple tools when it comes to how they function. Their job is to prevent the flow of contaminants from the system to thew supply line, even if the pressure from the supply line drops dramatically. This protects the water supply from contamination.

How they specifically prevent this backflow can vary based on the type of preventer, though the function stays the same.

Types of backflow preventers and who needs one

When shopping for a backflow preventer, it is important to understand which you need. There are a few different types of backflow preventers, including:

  • Air gaps – The most basic form of backflow prevention, they are simple vertical gaps allowing pressure to fluctuate safely
  • Anti-siphon valve – valves that normalize the pressure in the pipes when you turn the water off
  • Pressure vacuum breaker – an above ground regulator hooked to the main line
  • Double check type backflow preventer – a sturdy backflow preventer with two safeguards for more security
  • Reduced pressure type backflow preventer – a very secure backflow preventer which uses both checks and pressure regulation to prevent backflow. They are considered suitable for nearly any setup

The type you need will vary based on a number of things, such as if the irrigation system is on a residential or commercial property. Talk to your local irrigation professional to help decide which you should choose.

Certain areas also have regulations about which backflow preventer a system has to have. Backflow preventers must also be tested regularly.

If you are in doubt, contact your local water purveyor and ask for a list of approved backflow preventer devices for your zone.

Even if backflow preventers are not required by law in your area, they are highly recommended. Preventing chemicals and even foreign particles from entering the supply line keeps your water system healthy and free from blockages.

If you are uncertain if your irrigation system has a backflow preventer, call your local professional to have the system inspected. In northern New Jersey, Quench Irrigation can handle all your irrigation needs and keep your system running smooth for years to come.