What is Irrigation Backflow and How do Backflow Valves Prevent it?

What is Irrigation Backflow and How do Backflow Valves Prevent it?

Oct 27th 2023

Your irrigation system is key to maintaining a healthy landscape all year. When it comes to any irrigation system, backflow is a bad term. It's something that should not be taken lightly. Irrigation backflow can contaminate clean water in the mainline of your home, leading to diseases and irrigation problems. Backflow prevention is the most important component of an irrigation system. Backflow preventers or backflow valves are simple tools that can protect your water from being contaminated and save you trouble down the road.

But how does backflow happen, what is a backflow preventer, how does it work, and why do you need a backflow preventer on your irrigation system?

Don't worry. In this blog, we'll answer all these questions and many more to help you make your irrigation system free of contaminants. Let's begin!

What is an Irrigation Backflow?

Backflow refers to the contaminating water that flows in the unwanted reverse direction, causing pollution. During a backflow incident, water from the irrigation system may return to the main water supply system.

Backflow can occur at any cross-connection. It creates highly unsafe water when portable and non-potable water lines cross, as it happens in a reverse osmosis system.

Backflow is caused by one of the two types of variations in water pressure: Back Pressure or Back Siphonage.

Back Pressure: Back pressure occurs when the downstream pressure is much higher than the system pressure upstream. The common cause of back pressure is a drop in pressure in the supply line. Back pressure mostly develops in pressurized systems like pumps, boilers, and elevated tanks.

Back Siphonage: Back siphonage is when the vacuum upstream siphons water in the backward direction. It is caused by unexpected negative pressure in the supply line. It commonly results from an open fire hydrant or breakage on the water main.

Preventing contaminants from backflowing into potable water systems is imperative in commercial applications and home irrigation system settings. That's where backflow preventers come into play.

What is a Backflow Preventer and Why You Need One on Your Irrigation System

Backflow preventer devices are products designed to ensure water flows in one direction. Backflow preventers are installed on water pipes to protect against back pressure and back siphonage of polluted water from the irrigation system into the main water supply.

If you have an irrigation system, install a backflow preventer at the water meter. The water in irrigation lines contains harmful chemicals that can contaminate your potable water if the water flow reverses. Backflow contamination is hazardous to health. So, it is crucial to install backflow prevention where cross-connection exists. The purity of your cleaning and drinking water is at risk if you don't have backflow prevention.

Benefits of Backflow Preventers

Here are the key benefits of installing a backflow preventer on your irrigation system:

Removing Impurities and Reducing Risk of Diseases: The primary benefit of backflow prevention is that it keeps the water clean by removing impurities. Keeping drinking water and wastewater separate prevents toxic chemicals from polluting the water, reducing the risk of health problems.

Improving Water Quality: Backflow preventers keep the water clean without any bad smell or taste. Also, it enhances the efficiency of your residential water system.

Preventing Pipe Damage: Backflow valves keep foreign objects from clogging and damaging your pipes. It saves you money and time on complicated pipe repairs.

Complying with Legal Regulations: In several regions, installing a backflow preventer is legally required. Hence, by installing a backflow preventer, you can ensure that local regulations are followed and avoid fines or penalties.

How Does a Backflow Preventer Work?

A backflow preventer is a simple yet well-designed device that prevents contaminated water from reversing into the main supply line. The backflow valves allow the water to flow through one direction and then close when pressure re-enters. If any pressure coming back to the water main exceeds that of the route of flow, then the valves close, preventing backflow. The backflow valves are installed in pairs or series. Another type of valve that can prevent backflow is the Anti-Siphon valve. These valves are a combination of control valves and atmospheric backflow preventers. The backflow prevention function of these valves keeps your irrigation water from going back into your home drinking water.

Inspecting your backflow prevention devices once or twice a year by a qualified professional for wear and defects is essential. It is essential to inspect your backflow prevention devices once or twice a year by a qualified professional for wear and defects.

How to Choose the Right Irrigation Backflow Device for Your Irrigation System

When purchasing a backflow preventer for your irrigation system, it is crucial to understand your system needs and choose accordingly. Backflow preventers come in different types. However, no matter the type, all preventers serve the same purpose of protecting potable water lines from contaminants. Here are the three common types of backflow prevention devices and their installation process.

Air Gap

Air gap is the basic and inexpensive backflow preventer commonly used in sinks and bathrooms. They're simple vertical gaps used to prevent backflow with air gaps. Air gaps offer a barrier between the water main line and the water container. This way, polluted water stays in pipes and cannot enter faucets or showerheads.

Air Gap Installation:

Installing the air gap is a simple task. These preventers are used for taps and sinks. Find or drill a hole for the air gap so that water can return to sink in the event of backflow. Follow the product instructions when installing the device and assembling the air gap in the hole. Install the air gap in a vertical position. Secure the connections tightly to prevent leaks.

Check Valves

Check valves are sturdy backflow preventers that ensure water only flows in one direction. These valves open and shut depending on the pressure on the sides of the valve. When the pressure on the incoming side is higher than on the outgoing side, the valve opens, and water flows normally and vice versa. You can install check valves at individual water outlets as they're built for constant pressure systems.

Check Valve Installation:

Check valves come in multiple types, and installation can vary depending on your purchase type. It's best to check the installation instructions of your check valve on a manual. Here are a few general installation tips:

  1. Install the check valves in the correct direction of flow. If fitted backward, the increased pressure can lead to damage.
  2. Ensure the valves are installed in accessible locations so you can access them easily for testing.
  3. Flush the pipelines prior to installation.
  4. Don't install these preventers in areas where frost is possible.
  5. Avoid over-tightening your check valve.

Atmospheric Vacuum Breakers

Atmospheric vacuum breakers are the latest backflow prevention devices that stop backflow in faucets, spigots, and hoses. They're often installed with lawn sprinkler systems to prevent back siphonage. Atmospheric vacuum breakers contain a check valve. When the system drops pressures, a valve opens an air vent. When the air vent is opened, it breaks the vacuum, and the water supply line is closed. This process stops back siphonage when pressure is lost in the supply line.

Atmospheric Vacuum Breaker Installation:

The installation of a vacuum breaker preventer is simple. To install the breaker, screw it onto your faucet, spigot, or hose. It would help if you ensured the breaker you buy fits the size of the system you want to connect to.

The Bottom Line

Installation of backflow preventers is crucial to ensure the water flows in one direction, keeping your water system healthy.

At DripWorks, we carry a range of backflow prevention devices and valves to help you choose an affordable and easy backflow solution. You can select the product that suits your system requirements.

Which backflow preventer is best for your irrigation system? Feel free to call us at 1-800-522-3747 from Mon-Fri. Our irrigation experts will help you decide which prevention device to choose.