Best backflow preventer for sprinkler systems

Maintaining a landscape is hard work, and yet you require it to flourish and grow, but it is hard to do it without some irrigation involved. Irrigation is great, but you also need a backflow preventer to protect the rest of your water supply and prevent contamination.

If you are relying solely on the main city water line for all your needs, then you risk experiencing issues with backflow because of the changes in water pressure. The same contamination happens through pesticide sprayers, hose-attached sprinklers, and spray nozzles, which necessitates installation of a backflow prevention system.

However, what exactly do you choose when looking for these preventers? What are the factors to consider? What if the preventer does not work for you? These questions and more can make you feel uneasy on where to start, but we will outline three models to look out for, as well as the factors you should keep in mind.

Best backflow preventers for sprinkler systems – Comparison table

 
Hydrostatic testing pressure
Maximum pressure of working water
Maximum water temperature
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Febco 765-1” breaker
300 PSI
150 PSI
140OF
Zurn 720A Wilkins vacuum breaker
300 PSI
150 PSI
110OF
Homewerks worldwide pressure breaker
250 PSI
130 PSI
180OF

Febco 765-1” breaker – best for a small residential unit. Our choice

The reason why this is our choice is that it protects against a variety of issues with backflows, regardless of whether the pollutants are hazardous or non-hazardous.

Features

  • The entire structure of the preventer is bronze, in order to boost durability
  • The assembly is made easy through the single check valve and air opening
  • It can seal its air opening even when water flow is low through its lightweight poppet
  • Reduction in head losses through its design
  • All the parts are easy to service

The structure of the entire system has a spring-loaded check valve, which automatically closes when the water flow pressure drops below 1 PSI, or when the water flow is zero. At the same time, the air relief valve opens automatically as well. The check valve will then close when water flow increases, as the air relief valve closes.

There is something to note when you want to prevent its damage during the colder months of the year – make sure that you allow the valves to remain open at an angle of 45 degrees. This will stop any trapping of water between the ball valve body and the ball, and therefore prevents freezing and resulting damage from occurring.

Pros

  • Very easy to install
  • Offers you reliable service for a long time
  • Does not go through many cracking problems

Cons

  • Tends to be pricey depending on the seller

Verdict

This backflow preventer is actually the most durable and heavy-duty choice here, as long as you install and maintain it properly.

 

Zurn 720A Wilkins breaker – best for budget buyers

Unlike many backflow preventers in the market, the Zurn 720A seeks to protect you from high-hazard possibilities in your water system. It is also among the most cost-effective and low-maintenance choices, whether you are dealing with a commercial or residential system.

Features

  • Stainless steel fasteners on a bronze body
  • Highest water temperature of 110OF
  • A hydrostatic test pressure of up to 300 PSI

The whole structure of the pressure breaker is meant to prevent backflows through withstanding pressure drops. The process is through the inclusion of highly resilient shut-offs, and these will let you control both the check and air inlet valves as frequently as you want. The rest of the preventer is comprised of durable plastic, which includes the check assemblies, poppet, and bonnet, and these will guard against damage from freezing conditions.

Pros

  • Easy to install and repair when it breaks down
  • Employs the use of high protection standards
  • Promotes the efficient saving and use of water
  • The tapped bell valves make it easy to install
  • Resistance to rust and corrosion

Cons

  • As it ages, it can tend to break down in winter

Verdict

This is a very good budget-friendly option if you want a prevention system to start with, although you need to check on it frequently in the colder months of the year.

 

Homewerks Worldwide breaker – best for versatility

This preventer aims to help you stop any contaminants from entering your portable water supply, and is versatile enough to handle some more tasks.

Features

  • You can use it with any standard hoses and end valves
  • Brass construction that prevents rust
  • Allows permanent attachment through the break-off screw

It is possible to operate it at a maximum temperature of 180OF, and you can also remove its screw set through the self-draining vacuum breaking feature.

You will particularly like that you can use it with standard hoses and end valves, while trusting it to provide quality service for a long time due to its corrosion resistance.

Pros

  • Easy installation
  • Reliable with a variety of valves and hoses
  • Minimal water spillage issues

Cons

  • Struggles with water timers

Verdict

You will enjoy using this breaker, as long as it works well with your pipes. Rather than removing its screw set though, keep them in place to cater for any problems caused by hard water in the system.

 

What are backflow preventers?

A backflow preventer is part of a safety mechanism that stops contaminants from entering into a water supply. The usual case is that irrigation backflow devices are meant to work alongside portable water lines (also known as clean water supplies for drinking) in order to prevent backpressure and back-siphonage of contaminated water into your clean water supply.

Many areas actually require them as part of building code laws – but even though this might not be the case, they are still important to promote both short and long term safety. If the valve experiences some damage or issues and you lack a backflow preventer, then the chemicals from the contaminated water (like animal waste, pesticides, and fertilizers) can easily flow backwards to the clean water supply.

In addition, wells will also need a backflow prevention system, even if you are not getting your drinking water from them. This is because they protect the aquifer that the well sources the water from – especially if you are applying farming chemicals through your irrigation system.

The types of backflow preventers for sprinkler systems

Control valves

These are specialized valves that you can easily control the drip system or sprinklers from by turning them off or on. The usual case you will find is an irrigation system that has several valves of this type, with each controlling the irrigation rates in different parts of the lawn. You can either go for a manual control system or an automatic one.

Anti-siphon valves

These are control valves that are either automatic or manual, and they have an in-built atmospheric vacuum breaker. Their mode of installation must be at least 150mm (6 inches) above the highest drip emitter or sprinkler head, but never install them underground.

They are also common in residential piping systems due to their affordability, although some laws will not allow their use – so it is always best to check if you are unsure. They will also tend to spill water at times, so position them in an area where this will not be a problem.

AVB (Atmospheric Vacuum Breakers)

These are the most common types of backflow prevention systems, and are also the most affordable option. You will need to install them on your pipes just after the control valve.

Note that if the AVBs are what you are using, you must install one breaker after each control valve in your piping system – without any exceptions. You must also install them at a minimum height of 150mm (6 inches) above the highest drip emitter outlet, bubbler, or sprinkler head that you are controlling through the control valve.

That said, you may or may not choose to install an AVB at a point where it is underwater, like boxes below the ground. The installation requirements make AVBs impractical for when you have more than 6 valves, so you will need to consider a PVB (pressure vacuum breaker) in this case.

PVB (pressure vacuum breakers)

This is similar to an AVB, with the exception that you will only need one, and you will install it on the main line that leads to the control valves. Its installation is similar to AVB because of being at least 6 inches above the highest sprinkler head.

Note that the PVB might spill at times, although you can reduce this through installing a check valve that is spring-loaded just after it.

How to choose a backflow prevention system

You will find that there are several varieties of backflow preventers you can get in the market, so always ensure you check on your options. If you are unsure, you should check with your government building department (those that issue building permits) or your local water provider, in order to ensure the preventer you install is legal where you live.

Here are some things to keep in mind:

Where is the unit to serve?

One of the major aspects to think is whether the backflow prevention unit is to serve a single family household or a commercial enterprise.

If it is for a commercial enterprise, then it should cover any business properties, which include apartment complexes. In this case, you should always go for a reduced pressure type backflow preventer, as this is the standard in the industry and gives the entire portable water system the highest protection levels. For the case of a single family residential household, then move to the next criteria.

Are you planning on applying anything to your water supply through the irrigation mechanism?

You need to know whether you want to use irrigation (such as if you want to do some insect control), application of fertilizer, or fertigation (injecting the fertilizer into the irrigation water), as well as any other applications. Note that this will include any product that is labelled as ‘safe’, ‘natural’, or ‘organic’, including ‘safe’ mosquito or insect repellents that sprinklers and misters apply.

It is important to know that these products will end up in your irrigation water somehow, so they can be dangerous when they are highly concentrated in the pipe water you use. If this is the case or a concern for you, consider installing a reduced pressure type system.

Whether you want to install the preventer underground

If you want to place the prevention system below ground, then a double check type preventer will work the best, as it is the only preventer type that can allow underground installation. If you are going for another preventer type, you will need to install them in a big vault that has unlockable drainage.

The case is different if you are installing the preventer at least 6 inches above the drip emitters or sprinkler heads, as this allows you to use any backflow prevention system you want.

Is the irrigation area small or large?

If the area you want to irrigate is a large one, then you can use various backflow preventers. If it is small though, you can install the preventers at a height of 6 inches above the ground and put a cover over them if you wish. If you do not want to, then install and use specialized valves in your piping system that prevents siphoning.

Final thoughts

As you might probably see, choosing a backflow prevention system is not easy and requires you to do plenty of homework. Hopefully, these tips will guide you on what to do and what to look for when searching for one, and make sure that it fits your needs.

FAQs

Why exactly do I need a backflow preventer in an irrigation system?

All systems of irrigation will contain dihydrogen monoxide, a tasteless and odorless chemical that can easily kill millions of people and animals when inhaled. Since irrigation water is considered as a contaminant due to the contaminants present, the backflow preventer does the job that valves cannot – it stops backflow through protecting you in case the valves break down.

Are double-check backflow preventers and dual-check backflow preventers the same?

No, they are not, even though they seem to be very similar. A Double Check preventer will have small outlets that stick out its sides (test cocks) that you can use to connect it to test gauges, and a Dual Check will lack these test cocks.

William Smith

William Smith has been rendering his services to a botanical garden for the better part of his adult life and has recently moved to landscaping firms. His love for gardens has been nurtured since he was a kid, evident from the various garden centers and estates that have benefited from his services. Smith is a natural when it comes to gardening and when combined with his acquired degree in landscape design, you can expect a high-quality professional job, thanks to his experience and expertise. During his free time, Smith does gardening as a hobby and runs forums where he offers expert ideas on gardening.

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