Key Points
- Choose a backflow preventer based on system complexity—AVB for single-zone, PVB for multi-zone, DCVA for low-risk, and RPZ for high-risk systems with chemicals.
- Install devices per code: AVBs and PVBs must be above ground; DCVAs can go underground; RPZs need drainage for discharges.
- Regular inspections and proper selection prevent contamination, meet legal requirements, and avoid costly fines or water supply risks.
Don’t Let Dirty Water Flow Back Into Your Life
Ever wonder if your sprinkler system could actually contaminate your home’s drinking water?
Or if there’s a way to prevent harmful backflow without overcomplicating your setup?
This post breaks down the different types of backflow preventers made specifically for lawn irrigation systems—how they work, where they’re used, and how to choose the right one for your yard.
By the end, you’ll know exactly how to protect your water supply, stay on the right side of local plumbing codes, and avoid costly mistakes.
Need help deciding which backflow preventer is right for your irrigation installation?
Give Simmons Landscape and Irrigation a call or fill out the contact form—we’ll help you get it done right the first time.
Types of Backflow Preventers for Irrigation Systems
Choosing the right backflow prevention device starts with understanding the different types of backflow preventers available.
Each one works a little differently, and some are better suited for residential use than others.
Atmospheric Vacuum Breaker (AVB)
- How it works: An air inlet valve opens when water stops flowing, preventing back-siphoning from the downstream piping.
- Best for: Single-zone sprinkler systems without continuous pressure
- Limitations: Can’t be used with constant pressure or installed downstream of shutoff valves
- Pros: Inexpensive, easy to install
- Cons: Only protects one zone at a time; not testable
- Related term: Atmospheric vacuum breaker assemblies (AVB)
Pressure Vacuum Breaker (PVB)
- How it works: A spring-loaded poppet and air inlet valve work together to block contaminated water from reversing
- Best for: Multi-zone lawn irrigation systems
- Installation: Requires above-ground installation, at least 12 inches above the highest downstream point
- Pros: Affordable and testable backflow device
- Cons: Can crack in freezing temperatures
- Also known as: Pressure vacuum breaker assembly or pressure vacuum breaker PVB
Double Check Valve Assembly (DCVA or DC)
- How it works: Two spring-loaded check valves stop backflow by closing when back pressure or negative pressure is detected
- Best for: Low-hazard applications where there are no chemicals or fertilizers in use
- Installation: Can be installed in-ground, often in a vault
- Pros: Durable, allows for underground installation
- Cons: Not approved for high-hazard systems
- Also referred to as: Double check valve, double check valve assembly, double check detector assembly, or double check assembly
Reduced Pressure Zone Assembly (RPZ)
- How it works: Includes two check valves with a relief valve in the middle that opens when pressure drops
- Best for: High-risk systems with chemical injectors, non-potable sources, or commercial use
- Installation: Must be above ground, requires proper drainage for discharges
- Pros: Provides the highest level of backflow protection
- Cons: Costlier, larger, and needs regular testing
- Also called: Reduced pressure zone, reduced pressure zone assembly, or reduced pressure detector assembly
Quick Comparison Chart: Which Backflow Preventer Fits Your Needs?
With several types of backflow preventers to choose from, it helps to compare them side by side.
Here’s a simple breakdown of how each backflow prevention device stacks up in terms of usage, protection level, complexity, and cost.
| Type | Best Use Case | Level of Protection | Installation Complexity | Cost |
|---|---|---|---|---|
| Atmospheric Vacuum Breaker (AVB) | Single-zone sprinkler system | Low | Easy | $ |
| Pressure Vacuum Breaker (PVB) | Residential multi-zone systems | Moderate | Medium | $$ |
| Double Check Valve Assembly (DCVA) | Low-risk residential irrigation | Moderate | Easy | $$ |
| Reduced Pressure Zone Assembly (RPZ) | Fertilizer use or commercial properties | High | Complex | $$$ |
This chart gives you a snapshot of the common backflow preventers used in home irrigation setups.
Follow the link to learn about all the parts of an irrigation system.
Still not sure which is right for your property?
Keep reading—your choice depends on more than just cost or ease of installation.
How to Choose the Right Backflow Preventer for Your System
When it comes to backflow prevention, there’s no one-size-fits-all answer.
Your yard’s layout, local codes, and what you run through your irrigation system all matter.
Key Factors to Consider
- Type of Irrigation System
- A basic sprinkler system with no chemical use may only need an atmospheric vacuum breaker.
- Complex systems with multiple zones and chemicals likely require a reduced-pressure zone assembly.
Follow the link to learn more about the different types of irrigation systems.
- Fertilizer or Chemical Use
- If your system uses injectors for fertilizers, you’ll need a backflow prevention device that handles back pressure, like a reduced-pressure zone or double-check detector assembly.
- Water Pressure and Flow Requirements
- High water pressure systems may demand spring-loaded check valves and a design that can handle constant flow.
- Installation Location
- Some types of backflow preventers (like PVBs) must be above ground and at least 12″ above the highest point of downstream piping. Others, like the check valve assembly DCVA, can be installed below ground.
- Compliance with Local Codes
- Areas with strict regulations around drinking water protection may require test cocks and shutoff valves as part of the backflow setup.
- Budget and Maintenance
- While a double check valve may cost less up front, a reduced-pressure zone assembly offers better long-term backflow protection in high-risk areas.
Choosing the wrong backflow device could put your potable water supply at risk.
When in doubt, it’s smart to consult a certified backflow specialist to ensure your system is functioning properly and meets local safety standards.
Do You Need a Backflow Preventer?
Yes—if you have an irrigation system, you likely do need a backflow preventer.
Most local codes across this region require some form of backflow prevention assembly for residential lawn systems, especially when there are cross connections that could allow contaminated water to flow into the potable water supply.
For example, per the City of Toledo, you are required to take precautions to prevent contamination of the public water supply, including installing an appropriate backflow prevention device.
Why It’s Required
When your sprinkler system connects to your home’s drinking water system, it creates a potential hazard.
If backflow occurs, fertilizers, lawn chemicals, or dirty runoff can enter your home’s pipes. This risk is why building codes mandate specific types of backflow preventers be installed and maintained.
When Inspections or Permits Are Needed
- Many towns require permits for new irrigation installs—backflow protection must be included in the design.
- Annual inspections or certifications may be necessary for reduced-pressure zone assemblies, double-check valve assemblies, and other testable units. The landscape contractors at Simmons Landscape and Irrigation always check the backflow preventer as part of our irrigation inspection service.
- Some areas require the use of shutoff valves and test cocks to allow for proper maintenance and inspection of your backflow assembly.
What Happens If You’re Not Compliant
Skipping or failing to maintain a backflow prevention device isn’t just risky—it can also lead to fines, water service interruptions, or forced retrofits at your own expense.
Protecting your check valve system means protecting your home and everyone who drinks from your tap.
Signs Your Backflow Preventer Needs Repair or Replacement
Even the best backflow preventers can wear down over time, especially in areas with shifting weather and heavy use of sprinkler systems.
If your backflow assembly isn’t functioning properly, it puts your entire water system at risk.
Watch for These Warning Signs:
- Visible Leaks or Drips
Water dripping from the relief valve or seams of the device may indicate internal failure or worn parts. - Sudden Pressure Drops
A loss of pressure in your irrigation zones could mean one of the spring-loaded check valves isn’t closing correctly. - Discolored or Foul-Tasting Water
If your tap water smells, tastes odd, or appears cloudy, the device may not be stopping cross connections effectively. - Failed Annual Inspection
If a licensed tester finds issues with the shutoff valves, internal checks, or air gap, your system may require replacement.
Follow the link to learn more about troubleshooting and repairing sprinkler systems.
📌 Backflow issues don’t just affect your yard—they could allow fertilizer contaminated water into your potable water supply. Stay ahead of trouble by replacing aging or malfunctioning units before they fail completely.
Backflow Prevention Myths (And the Truth Behind Them)
There’s a lot of confusion out there when it comes to backflow prevention.
Let’s set the record straight so you don’t fall for outdated advice.
“Only Commercial Systems Need Backflow Prevention”
False. Even a basic garden hose connected to a hose bib can create a dangerous cross connection.
Residential systems, especially those with control valves and sprinkler heads, can absolutely contaminate the drinking water supply if left unprotected.
“Once It’s Installed, You’re Set for Life”
Wrong. All backflow prevention assemblies need regular inspection, and some parts—especially in atmospheric vacuum breaker units—can wear out quickly.
Moving parts like spring-loaded check valves need to be tested and maintained.
“Any Backflow Device Will Do”
Not true. The right choice depends on your system’s layout, pressure, and exposure to chemicals.
For example, an air gap might work for a drain line, but not for an underground irrigation system.
A high-risk setup often needs a relief valve-equipped unit like a reduced-pressure zone assembly, not just a basic AVB.
✅ Avoiding these myths helps protect your home, your family, and the broader water system shared by your neighbors.
Protect Your Water, Protect Your Home—Trust Simmons Landscape and Irrigation
Now that you know the different types of backflow preventers, how they work, and how to spot problems before they start, you’re better equipped to keep your irrigation system safe and compliant.
From choosing the right backflow prevention assembly to understanding maintenance requirements, every step matters when it comes to protecting your water supply.
If you’re ready to upgrade your system—or just want peace of mind that your current setup is doing its job—the irrigation experts at Simmons Landscape and Irrigation are here to help.
Whether it’s a new installation, backflow testing, or repairs, we make it easy to protect what matters most.
