Sprinkler Backflow Preventer Guide

Sprinkler systems and other irrigation lines are a constant source of plumbing problems – and backflow is one of the most common! Backflow water can cause a serious health problem if it contaminates drinking water.

Luckily our team of experts will teach you everything you need to know about a sprinkler backflow preventer – including what they do, potential problems, our favorite models, and other important information to help install a backflow device and protect your water supply

What Does A Sprinker Backflow Preventer Do?

A sprinkler or irrigation system backflow preventer is a one way valve that allows water to pass into the sprinkler system out to the lawn sprinkler but prevents it from returning into the water supply which can be harmful to your health. Water flowing the wrong direction can also cause damage to your irrigation system so it is important to have a working valve.

How Can Backflow Damage My sprinkler Irrigation System?

Backflow water can damage a sprinkler system by ‘overflowing’ the pipes and causing a leak. Sometimes the problem will happen right away with a broken pipe but in other cases it can cause small damage over many years – eventually resulting in a small leak.

Additional Parts and Accessories Warning

If you do not have a backflow valve attached to your lawn sprinker system your other attachments like alarms and timers!

Best Sprinker Backflow Preventers

Zurn 710
Zurn 710 Pressure Vacuum Breaker Assembly
Things to Know
Made of bronze
Top pick under $75
Fits 3/4″ lines
Max 150 PSI and 140°F

Our pick for the best sprinkler and irrigations System preventer is the Zurn 3/4″ 710 Pressure Vacuum Breaker Assembly. This valve is made of bronze and specifically designed to prevent backflow on potable water lines.

The valve is light weight, and has a few moving parts which means it has a long working life with few maintenance or mechanical problems.

It is a popular choice for areas without a lot of room it has a very compact body. Plus, the valve is made by Zurn so you know it will be built to last!

Types of irrigation backflow prevention devices

There are 3 types of backflow devices for irrigation and sprinkler systems. Each style offers pro’s and con’s as well as different installation requirements

Types of sprinkler backflow preventers
  • Pressure vacuum breaker assembly valves – This style of valve is the most common on home sprinkler systems. They are simple to install and maintain but need to be installed vertically and can’t be used in drain lines with backpressure.
  • Double check valves – Double check valve assembly devices (DCVA) are the best style to use on lawn sprinkler systems. They work well with water lines buried underground and work be when installed horizontally for easy installation on lawn watering systems. Another advantage is this type of device can be installed in lines with backpressure.
  • Reduced pressure zone assembly – A RPZA backflow preventer is the most dependable type of valve – but also the most expensive. They need to be installed above ground – but unlike other types of pressure breaker valves – this type can preventer fertilizer backflow (a common cause of failing backflow testing).

Why You Need A Irrigation Backflow Preventer

Not everyone is sold on why they need an irrigation backflow preventer. If your system is fed from a potable water supply most places will require a backflow valve and a yearly backflow test during a backflow preventer inspection (performed by city regulators or testers trying to ensure clean water)

The second most common reason is to protect the system from water damage. A lawn sprinkler system is an investment – and costly to replace since you will need to dig up and replace the old system. A backflow prevention device can go a long way in preventing this type of damage to irrigation and water lines.

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How to Choose

Not sure which type of model to choose? Most home sprinkler and irrigation systems can use a pressure vacuum breaker like the Zurn 710. They are affordable and highly effective. One type of valve we do not recommend is an atmospheric vacuum breaker. These valves are not as reliable and will not pass city inspection if it connected to the water system.

Are backflow preventers required by law?

Yes, many cities require a backflow prevention assembly to keep clean drinking water.

Is backflow common in sprinkler systems?

Backflow is not common, but it can cause damage to your lines so it is important to have a protection valve

Do you need a backflow preventer on sprinkler systems?

Yes, many local governments require a backflow valve if it is attached to the potable water system.

How much does it cost to install a backflow preventer?

Installing usually costs between 500 to 700 dollars depending on the location of the valve and the amount of time to install