Water Safety & Compliance
Backflow Information
Backflow prevention protects your drinking water from contamination. Every irrigation system needs it. Here's what you need to know about backflow, the devices that prevent it, and how EZ-FLO systems meet safety requirements.
What is Backflow?
The American Backflow Prevention Association (ABPA) defines backflow as the undesirable reversal of water flow through a cross-connection into your drinking water system. Two types can occur in irrigation systems: backpressure backflow and backsiphonage. Almost all local plumbing codes require irrigation systems to have a proper backflow prevention device installed. This isn’t optional. It’s the law in most jurisdictions.
Understanding the Risks
Types of Backflow
Two distinct mechanisms cause backflow in irrigation systems. Understanding both helps you choose the right protection.
Backpressure Backflow
Backpressure backflow happens when downstream pressure exceeds upstream supply pressure. This forces non-potable water back into your drinking water system. Causes include pumps creating additional pressure, thermal expansion in closed systems, or elevation changes where irrigation zones sit higher than the water source.
Common Causes
- Pumps creating higher downstream pressure
- Temperature increases in boilers
- Elevated irrigation zones above PVB installation
- Supply pressure reduction during high demand
Backsiphonage
Backsiphonage occurs when negative pressure (a vacuum) develops in the water supply line. The effect works like drinking through a straw. Water main breaks, fire hydrant use, or sudden high-demand situations can create this vacuum, pulling contaminated water backward into clean supply lines.
Common Causes
- Nearby fire fighting activities
- Water main breaks
- Water line flushing operations
- Sudden stoppage of water supply
System Overview
Backflow Prevention Devices
This diagram shows where EZ-FLO fits in a properly protected irrigation system. The backflow preventer always goes between your water supply and the EZ-FLO unit.
- Pressure Vacuum Breaker protects water supply
- EZ-FLO tank installed after backflow preventer
- Zone valves control irrigation areas
Safety Requirements
Backflow Prevention Devices
Several types of backflow prevention devices work with irrigation systems. Only specific types should be used with fertigation. Here’s what you need to know.
Important Requirement
Every EZ-FLO installation requires an appropriate backflow prevention device. This applies to main-line systems, hose-end units, and drip systems. Follow your local plumbing codes. If a contractor tells you backflow protection isn't needed, find another contractor.
Reduced Pressure Zone
The RPZ contains two spring-loaded check valves with a pressure differential relief valve between them. Shutoff valves and test cocks on each end allow annual testing. This is the highest level of protection and works against both backpressure and backsiphonage.
Backpressure Protection
Backsiphonage Protection
Health & Non-Health Hazards
Pressure Vacuum Breaker
The PVB has a spring-loaded check valve and a spring-loaded air inlet valve on the discharge side. It protects against backsiphonage only. PVBs must be installed at least 12 inches above the highest sprinkler head or emitter.
Backsiphonage Only
Health & Non-Health Hazards
Anti-Siphon Valve
For hose-end EZ-FLO units connected to outdoor faucets, the minimum requirement is an anti-siphon valve installed upstream from the connection point. Many hose bibs have these built in. Check yours before installation.
Hose Bib Systems Only
Minimum Requirement
Review by National Standards Setting Body
We submitted our fertigation system to the University of Southern California’s Foundation for Cross-Connection Control and Hydraulic Research. This organization tests and certifies backflow prevention devices. Every major manufacturer in the industry submits their products here for approval.
In May 2004, the Foundation classified EZ-FLO systems as aspiration devices, not injection devices. The key difference: EZ-FLO operates under ambient water pressure and cannot add backpressure to the system. The minimum acceptable backflow prevention device is a Pressure Vacuum Breaker (PVB). Reduced Pressure Zone (RP) assemblies are also acceptable and required by some local codes.
Unlike mechanical injectors or pumps, EZ-FLO systems use differential pressure within a closed loop. No moving parts. No motors. No additional pressure introduced to the system.