Anti Siphon Valve Vs. Backflow Preventer: What Is The Difference?

When you start getting into the world of plumbing, one of the things that happens is you gain a new vocabulary. This even boils down to aspects of plumbing most take for granted, such as the anti-siphon valve or a backflow preventer. Speaking of, these two terms are often used interchangeably. What do they mean, and what kind of valve do you need for your project?

The term “backflow preventer” is an umbrella term that covers the mechanisms used for ensuring that water does not reenter the public water system once it’s been sent through an irrigation system. An anti-siphon valve is a specific kind of backflow preventer, making it a subcategory of the umbrella term.

These two terms are understandably confusing, especially if you’re green to the world of irrigation. This guide will help you understand what’s going on with this stuff.

While there are some other uses for them, most people know backflow preventers as a tool that guards against water contaminating the public water system. These are mandated for irrigation systems, primarily because of the concern of having soil and other contaminants travel back into the public’s water supply.

Every irrigation system needs to have at least one backflow preventer to help ensure that the water supply stays clean. Without it, the negative pressure that occurs in the system could get fertilizer and pesticides to leech back into the supply.

You don’t need a backflow preventer for everything. You just need them for moments where water could come into contact with soil or other contaminants. That’s why you need to use them in irrigation systems as well as in places like the tap where your hose gets connected. Each state has its own codes when it comes to installing a backflow preventer, so it’s always good to find out what yours says.

Reading municipal ordinances about backflow prevention can be difficult, but as long as you know what to look for, you should be alright. Any time that you hear the phrase “cross-connection control,” they’re usually discussing backflow prevention.

An anti-siphon valve, also known as an ASV, is a type of backflow preventer that is most commonly used in residential systems. They’re actually the most popular, but not because they are very efficient in preventing backflow. Rather, they’re popular because they are simple to install and cheap.

Anti-siphon valves work through the use of a built-in atmospheric vacuum breaker. In other words, it helps break the suction that causes water from outside to re-enter your system. In some cities, anti-siphon valves are also called as AVBs due to their atmospheric vacuum breaking abilities. However, they are NOT AVBs.

This is a little tricky. The best go-to solution here is to talk to an irrigation specialist who’s setting up your sprinkler system to help you figure out what kind of backflow prevention you need. They tend to know the local ordinances fairly well and also can tell you which backflow preventer would be better for your particular irrigation setup.

On the other hand, there are also ways that you can figure it out for yourself. The best way to look at it is to take a look at each backflow prevention device and examine what kind of uses they offer. Once you take a look at the uses and find a couple that would suit your needs, check local ordinances to see which ones are approved for use in your area.

A backflow preventer can vary greatly depending on what kind of device you intend on using in your system. Studies show that a backflow preventer can cost anywhere from $35 to over $900 for the part alone—with Reduced Pressure Assemblies being the most expensive type to purchase.

The backflow preventer’s installation costs can vary too. If you install it on your own, you won’t have to worry about this issue at all. On the other hand, if you need to have a professional installer do the job, it will cost between $30 to $250. This brings the whole price tag up significantly.

Overall, installing backflow prevention in your yard will cost between $75 to $1150. This makes it one of the most expensive aspects of your irrigation system.

Related Questions

What Is The Difference Between A Backwater Valve And Backflow Preventer?

A backflow preventer connects to your home’s water line and works to ensure that potentially contaminated water doesn’t leech back into the water supply. It’s there to make sure that water sits in your system where it’s supposed to.On the other hand, a backwater valve connects to your home’s sewer line rather than the waterline. Backwater valves are there to prevent dirty water from entering your home’s water line when the city’s sewage flow is too much for the system to handle.

Who is responsible for paying for backflow prevention?

Part of being a homeowner means that you have to be in charge of keeping your home up to par. This includes making sure that the irrigation system won’t leech fertilizer into the city’s water tables. As a result, all cities and towns put the burden of choosing (and maintaining) backflow prevention on the homeowner.With that said, there may be specific incidents where you may be able to call up the municipal offices and ask for help. This includes finding something on your property that could potentially harm your backflow prevention endeavors, such as a water line that was unannounced.

What happens if you have an irrigation system without backflow prevention?

The answer to this is simple yet devastating: fertilizers get into the waterline, which contaminates everything in your home’s water. Depending on how bad things get, the municipal court might also take notice of the contamination and narrow it down to your home. This could lead to fines, lawsuits, or even getting your house condemned depending on how bad it gets.