A Backflow Preventer for Irrigation Systems? Important Legal Info

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A backflow preventer (BFT) is a safety device attached to water systems, such as irrigation, to halt contaminated water from flowing back into the main water line. All states have policy guidelines on backflow preventers for all irrigation systems.

A backflow preventer for irrigation systems should be tested annually. This ensures backflow systems protect main water systems from contamination due to pesticides, fertilizers, and other chemicals. State fines for failure to test backflow systems cost up to $500 or result in water disconnection. 

The American WaterWorks Association (AWWA) considers irrigation systems a high hazard because of the potential risk to public health. A change in water pressure can cause contaminated water from irrigation lines to flow back to the main water systems. The rest of this article will explore backflow preventer guidelines and potential legal issues that may arise if you neglect to use a backflow preventer for irrigation systems. 

Where To Install The Backflow Preventer

The backflow preventer should be installed less than five feet above ground to limit the risk of cross-connections due to flooding. When the backflow preventer is above ground, testing and maintenance will be easier. However, some backflow preventers, like the double-check valve assembly (DCVA), are installed below ground.

Installation should also be outdoors to avoid the risk of backflow flooding your property. 

Some people would rather hide the backflow preventer for aesthetic reasons. However, this can be counterproductive if the backflow preventer isn’t installed outdoors and above ground. 

Why Installing a Backflow Preventer Is Important

In a perfect system, water would only flow in one direction. Unfortunately, this isn’t always the case. Water sometimes flows backwards because of a change in water pressure and water line breaks, resulting in the contamination of clean water with debris or chemicals. To keep this from happening, a backflow preventer is installed. 

Legal Info on Backflow Preventers for Irrigation Systems

Most irrigation systems use potable water systems. This water system is treated for microorganisms and other contaminants to meet state and federal water standards for human consumption. A flawed irrigation system can easily compromise these standards. 

Some of the policies for backflow preventers for irrigation systems include:

  • Irrigation systems with access points for injecting pesticides, herbicides, fertilizers, and other chemicals must have a backflow preventer or air gap. 
  • States, like Connecticut, Louisiana, North Carolina, Illinois, Texas, New Jersey, and Rhode Island require installers to get an irrigation contractor license or certification before installing an irrigation system. This is to ensure all irrigation systems have a backflow preventer.  
  • Property owners need to get lawn sprinkler permits. 
  • Before a lawn sprinkler permit is issued, some municipalities require a plumbing permit. Only licensed plumbers who understand city plumbing codes are given plumbing permits to install irrigation systems.  
  • A penalty fee is applicable if you install a sprinkler system before getting a lawn sprinkler permit. For example, in Texas, irrigating without a permit is considered a Class C misdemeanor attracting a penalty fee of $500 in addition to other costs. New York imposes a fine, and if you fail to pay, you risk having your water disconnected. 
  • Backflow preventers for irrigation systems should be tested regularly. Some states require testing of the system annually or every two years.

Here is a detailed video on compliance of backflow preventers for irrigation systems. 

Popular Irrigation Systems In The US

The primary difference in irrigation systems is in how the water is distributed. The type of backflow preventer you use will depend on the irrigation system and the source of water. 

Here are the different irrigation systems used across the US: 

  • Surface Irrigation: Surface irrigation doesn’t require a mechanical pump because water is distributed across the land using gravity. Backflow systems are not necessary for this system because there is no risk of backflow.
  • Drip Irrigation: Drip irrigation is localized, where water is delivered to the roots of plants through pipes. Runoff and evaporation are minimal.  
  • Sprinkler irrigation: Sprinkler irrigation is the most common method used in the US, where water is distributed from a central location through sprinkler systems. Some states require property owners to get a permit and install backflow preventers for sprinkler irrigation. 
  • Lateral Move Irrigation: Lateral move irrigation is labor intensive. It involves the use of pipes connected to a wheel and a set of sprinklers. You can rotate the wheel tower by hand when watering a specific area, or use a purpose-built mechanism that automatically moves the wheels in different directions. 
  • Sub-irrigation: Sub irrigation is used in places where the water table is high. Pumping stations, gates, canals,and ditches are used to raise the water table for irrigation. If this water is only used for irrigation, a backflow preventer may not be necessary. 
  • Center Pivot Irrigation: Like the lateral move irrigation, the center pivot irrigation system has a sprinkler system attached to the wheeled towers. The difference is this system is used in areas where the land is flat, and the sprinklers move in a circular manner.

Reasons for State Regulation on Backflow Preventer Testing

One of the reasons you test backflow preventers is because the authorities demand it. The penalty is a small price to pay, considering the risk of not carrying out regular backflow preventer testing. 

State regulation on backflow preventer testing is important because:

  • The authorities have a responsibility to provide clean water to residents. 
  • A public health crisis will come at a great cost to the authority, not just financially, but lives could be lost. 
  • Contamination may compromise some people’s quality of life.
  • Prevention of water contamination is easier and cheaper than cleaning out the entire system due to negligence.
  • Annual tests are cheaper for households compared to the lawsuits and other expenses they may have to foot should contamination originate from one of their homes. 
  • The regulations make the residents responsible for the quality of water they consume in their homes.
  • Regular preventative maintenance assures the authorities that the water running in homes is clean. 
  • Contamination in the potable water system is sometimes identified when a health crisis linked to poor quality water occurs. Instead of waiting for the worst to occur, the state prefers to have a system in place to prevent backflow. 
  • States also have a list of approved backflow preventers for irrigation systems. The approved assemblies include backflow preventers with test cocks and isolation valves. Regular tests help the authorities to monitor the types of backflow preventers used and if they meet the set standards.

What if You Don’t Get the Backflow Preventer Tested?

Getting a backflow preventer for irrigation systems tested can feel like an unnecessary cost and waste of time, especially when you have trouble remembering when to do it. However, you need to keep your records to ensure you don’t miss any tests.

If you don’t get the backflow preventer tested, you risk paying a hefty fine, which increases the longer you wait to test. Besides breaking the law, you’ll be putting your family at risk. A faulty backflow preventer doesn’t sound an alarm, and contamination won’t be noticed until it’s too late. 

The taste of contaminated water is different from clean water. Unfortunately, the change is gradual, so you would have consumed contaminated water when you noticed something was wrong. Having the backflow preventer tested annually or once every two years, as per your state’s regulation, is a guarantee that the water you use in your home is clean. 

What To Do When a Contamination Is Discovered

A cross-connection is the point when non-portable substances, such as pesticide and fertilizer mixtures, come into contact with potable water usually used in homes. Sometimes contamination in the cross-connections is discovered when the backflow preventer is tested.

When a contamination is discovered, you need to:

  • Immediately report to the department of cross-connection control.
  • Remove the uncontrolled connection.
  • Find out what went wrong.
  • Install a new, approved backflow preventer. 

You may be subjected to harsh penalties if you miss the regular tests and discover that your property has contaminated cross-connections. 

Types of Backflow Preventers for Irrigation

The type of backflow preventer you use will depend on the irrigation system and the specifications of those approved by your municipality. You should use a certified plumber to install your irrigation system because they know the backflow preventer to use. 

The three main types of backflow preventers for irrigation are:

Reduced Pressure Backflow Assembly (RPBA)

A reduced pressure backflow assembly (RBPA) is a state-approved backflow preventer that isolates irrigation systems that use injectors or pumps for applying fertilizer, pesticides, and other chemicals. It’s often used in lawn irrigation systems, installed above ground, and effective for protecting against backpressure and back-siphonage. 

It has two independent check valves and a differential relief valve that automatically opens between them. RBPA is the ideal assembly to protect against high-hazard contaminants.

A certified plumber should test the RBPA during installation, after a repair or relocation, and at least once a year. 

Double Check Valve Assembly (DCVA)

The double check valve assembly (DCVA) is suitable for isolating irrigation systems that don’t use pumps and injectors to apply fertilizer and other irrigation inputs. DCVA is installed below ground, and it has two single-check-valves, two shut-off valves, and four test cocks. 

This backflow preventer is ideal for medium hazard installations, like sprinkler systems. It protects against back-siphonage and backpressure. 

Pressure Vacuum Breaker Assembly 

The pressure vacuum breaker assembly (PVBA) is installed above the irrigation system’s highest point of the water source, preferably the highest sprinkler head or highest slope. The PVBA should be positioned at least 12 inches (30.48cm) above the highest irrigation piping. PVBA is designed to isolate irrigation systems that don’t use pumps or injectors to apply fertilizer and lawn chemicals. 

Atmospheric Vacuum Breaker (Anti Siphon)

The atmospheric vacuum breaker is ideal for a simple irrigation setup. Unfortunately, it’s also the least reliable and often not recommended by various localities, especially large cities and suburbs. This backflow preventer cannot sustain changes in water pressure. 

When using this backflow preventer, avoid the use of chemicals when irrigating the lawn because backflow risks are high. 

Do All Irrigation Systems Need a Backflow Preventer?

When installing an irrigation system, including the sprinkler for watering your lawn, you need to know the water source. This is what determines if you should use a backflow inventor or not. Authorities are mainly concerned about potable water systems piped to people’s homes and safe for drinking. 

Not all irrigation systems need a backflow preventer. Only irrigation systems linked to water that you also drink need a backflow preventer. When using the city water line, you must use a backflow preventer. Underground water specific for irrigation doesn’t need a backflow preventer.

Some states, like Colorado, have areas where dual irrigation systems are set up. In this case, some of the water comes from underground water, and some from the domestic water supply. A reduced pressure backflow preventer keeps contaminants from flowing back into the potable water. 

This video is an overview of backflow preventers and how they work on different irrigation systems. 

Why Use Certified Installers for Irrigation Systems

Besides the regulation to have a backflow preventer for your irrigation system, most states insist on using a certified installer. Some even have a list of contractors that residents can use to fix their irrigation systems. There are several reasons state and local authorities choose to operate this way. 

  • Certified installers understand the local design standards for irrigation systems. 
  • Some states are specific on the type of backflow preventer for different irrigation systems, and certified installers know the difference. 
  • The backflow devices have to be certified upon installation. Most localities lay this responsibility on their contract installers. 
  • Certified installers understand the risk, fines, and other costs you may incur if the wrong backflow preventer is installed or if the installation is poorly done. 
  • When you use a certified installer, you’ll have peace of mind knowing the water you’re using in the home isn’t contaminated with chemicals. It’s equally important for the entire community to use certified installers to guarantee everyone has clean water to use. 

Local authorities have simplified the process of getting the right backflow preventer. Some people unknowingly break the law because they don’t know what is required of them. Fortunately, certified installers are updated on the ideal backflow preventers to use. 


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