What is a Backflow Prevention Device, and How Does it Work?

Protecting the quality of your home's water supply is highly crucial. This can be achieved through the implementation of a backflow prevention device. This device is necessary to install in any situation where there's a chance of cross-connection between incoming potable water and irrigation water or wastewater. A backflow prevention device protects our potable water supply from contamination by preventing polluted water from entering the system. It protects your health and keeps your drinking and clean water safe.

In this backflow prevention guide, we'll review and see how it works, the different types available, and more. Let's delve deeper into how this device works and its role in irrigation systems to know the importance of having one installed.

What is Backflow and How Does it Happen

Backflow is an unwanted reversal of water flow in your irrigation or plumbing system, which can add pollutants or contaminants to your clean water. Water enters the system from the main water line; it should flow only in one direction of your irrigation system. However, due to pressure changes in pipes, contaminated water can flow backward into the potable mainline.

The water supply system typically works under a specific pressure range that allows water to move from the main supply line into the irrigation system. However, sudden water demand surge or water supply interruption can cause pressure to drop, which leads to back pressure. It forces water to reverse from the irrigation system back into the water supply. It can lead to contamination of potable water, resulting in health problems.

What is a Backflow Prevention Device?

A backflow prevention device is a tool that allows water to flow only in one direction and prevents the flow of contaminants from the irrigation system to the clean water supply line. Even if the pressure from the main line drops significantly, it protects the water from contamination. Consider a one-way gate that lets water from the water supply line flow into the irrigation system but stops water when it tries to flow backward into the water supply. A backflow preventer is installed at the water meter of your irrigation system or near any piping system that involves cross-connections.

How Does a Backflow Preventer Work

Most backflow prevention devices rely on check valves, which act like one-way gates. A backflow preventer uses checkpoints that respond to pressure to stop back siphonage. These points are basically check valves that open and close to allow normal flow and prevent reverse flow.

There are two independently functioning check valves with an empty space between them and a diaphragm that is activated by water pressure. When water flows normally from the main supply line to your system, the check valves stay open and allow it to pass through. When the pressure drops in the water supply, the pressure difference triggers the valves to close and prevent it from flowing backward.

Types of Backflow Preventers

Backflow prevention devices come in multiple types, each best suited for a particular application. All backflow preventers protect drinking water from being contaminated by treated irrigation water.

Pressure Vacuum Breakers

The PVB works best for low to medium applications such as irrigation systems. It combines the properties of spring, critical vacuum, and check valves to ensure that the system prevents backflow. The PVB device incorporates an air inlet valve that closes what water flows in the right direction and a check apparatus that prevents backflow. If the pressure drops, the air inlet valve opens, interrupting the siphon and blocking the return water. PVB prevents back siphonage into potable water.

Double Check Valve Assembly

A DCVA has independent double check-valves that provide the best solution for preventing back siphonage and back pressure flow. Double check valves to ensure water flows only in one direction. The valves open and close based on pressure on the sides of the valves.

When the water pressure is greater on the incoming side than the outgoing, the valve opens, and water flows normally. On the other hand, when pressure is higher on the outgoing side than the incoming, the valves close to prevent irrigation water from being pulled into the potable water line.

Reduced Pressure Zone Assembly

RPZs are designed for use in residential and commercial settings exposed to large levels of contaminants. They have two check valves separated by a chamber. These devices offer the highest protection by preventing backflow and actively removing contaminants that breach the first check valve. If a check valve leaks, the device expels water from the pressure relief valve and maintains a safe zone of low pressure. It also has a shutoff valve on the inlet and outlet for testing purposes.

Why You Should Install a Backflow Prevention Device

There are many benefits of installing backflow preventers. Some of the reasons that show why you should consider installing this device include:

Protect Your Health: Having a backflow prevention device protects your health. It does this by ensuring your drinking water remains clean and free from contamination. It prevents fertilizers, chemicals, and other additives from entering undesired places.

Maintain Water Quality: Backflow prevention devices keep water clean and maintain its quality. Failure to install these devices can contaminate the entire water source and render it useless.

Legal and Regulatory Compliance: In many municipalities, the installation of a backflow preventer is legally required. You must check backflow prevention system requirements in your area for specific types.

Backflow Prevention Device Maintenance

Your backflow prevention device requires regular maintenance for optimal performance. One of the initial steps of this process is to conduct routine inspections. Look for any visible signs of wear and tear, such as leaks or corrosion. If you identify any issues, address them immediately to prevent serious damage to your device.

You also need to monitor the pressure levels in your system. A sudden pressure drop is a sign of potential backflow. Lastly, test your backflow prevention device to verify that it operates correctly and can stop backflow.

The Bottom Line

A backflow prevention device is essential in protecting your home's water supply from contamination. Installing this device in your irrigation system is a good measure to maintain water quality, health, and peace of mind. Whether you're a landscape or property manager, understanding the installation and maintenance of this device is a responsibility.

If you're looking for the right backflow prevention device for your home's specific needs, DripWorks can simplify your buying process. We carry a wide range of backflow prevention devices made of brass or plastic to suit your needs. We also stock other valves and components to equip your irrigation system.