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Back Flows

Protect your potable water—and comply with code—by selecting the right back-flow prevention devices for your irrigation system. Our Back Flow Preventers & Parts collection offers trusted assemblies and accessories built for homeowners, DIYers, and pros alike.

Whether you’re installing a new lawn sprinkler system or upgrading an existing irrigation setup, a proper back-flow preventer is a critical safeguard. These devices stop the reversal of water flow—known as back-siphonage or back-pressure—which can draw fertilizers, soil bacteria, and other contaminants into your drinking water supply.

Shop by type

  • PVB (Pressure Vacuum Breaker): common for lawn irrigation; must be installed above grade and typically 12" above highest downstream outlet.
  • RPZ / RP (Reduced Pressure Zone): highest protection for high-hazard or fertilizer/chem injection; requires drain/relief discharge area.
  • DC / DCVA (Double Check Valve Assembly): used where allowed for low-hazard irrigation without chemicals.
  • AVB (Atmospheric Vacuum Breaker): zone-level protection; not for continuous pressure (typically one per zone where permitted).

What you'll find

  • Sizes: 3/4", 1", 1-1/2", 2" (select larger commercial sizes available)
  • Options & parts: union ball valves, test cocks, lead-free models, repair kits (bonnets, checks, relief assemblies), freeze covers
  • Brands: Febco, Watts Water, Apollo, Zurn (Wilkins)

Why choose Big Frog Supply? We focus on irrigation, plumbing and landscape lighting supplies—so you’re not just buying a part, you’re tapping into expert-curated gear, reliable inventory, and a partner who speaks “sprinkler system” language.

  •

    Febco - 860-QT-FS 2 - 2 IN Bronze Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff, Small Diameter, Backflow Flood Sensor F1316

    Febco
    $ 1.00 - $ 1.00
    $ 1.00
    $ 1,391.24
    $ 1,391.24 - $ 1,391.24
    $ 1,391.24

    2 IN Bronze Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff, Small Diameter, Backflow Flood Sensor  This item does not comp...

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    $ 1.00 - $ 1.00
    $ 1.00
    $ 1,391.24
    $ 1,391.24 - $ 1,391.24
    $ 1,391.24

  • Febco - T765FBV 1 1/4 IN Bronze Pressure Vacuum Breaker Backflow Preventer, Quarter Turn Shutoffs, Freeze Sensor

    Febco
    $ 653.33 - $ 653.33
    $ 653.33
    $ 756.03
    $ 756.03 - $ 756.03
    $ 756.03

    This 1 1/4 inch pressure vacuum breaker backflow preventer is used to protect against health hazard and non-hazard backsiphonage of toxic or non-t...

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    $ 653.33 - $ 653.33
    $ 653.33
    $ 756.03
    $ 756.03 - $ 756.03
    $ 756.03

  • Febco 11/2" T765GBV Pressure Vacuum Breaker 765-QT-FZ PVB 1 1/2 Bronze Pressure Vacuum Breaker Backflow Preventer, Quarter Turn Shutoffs, Freeze Sensor

    Febco
    $ 733.23 - $ 733.23
    $ 733.23
    $ 830.36
    $ 830.36 - $ 830.36
    $ 830.36

    This 1 1/2 inch pressure vacuum breaker backflow preventer is used to protect against health hazard and non-hazard backsiphonage of toxic or non-t...

    View full details
    $ 733.23 - $ 733.23
    $ 733.23
    $ 830.36
    $ 830.36 - $ 830.36
    $ 830.36

  • Febco U765-QT-FZ PVB 1 1 IN Bronze Pressure Vacuum Breaker Backflow Preventer, Quarter Turn Shutoffs, Unions

    Febco
    $ 217.32 - $ 217.32
    $ 217.32
    $ 217.32
    $ 217.32 - $ 217.32
    $ 217.32

    Lead Free: NO 1 IN Bronze Pressure Vacuum Breaker Backflow Preventer, Quarter Turn Shutoffs, Union Connections, Freeze Sensor   This 1 inch pressu...

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    $ 217.32 - $ 217.32
    $ 217.32
    $ 217.32
    $ 217.32 - $ 217.32
    $ 217.32

  • Zurn Wilkins 1-975XL 1" 975XL Reduced Pressure Principle Assembly

    Zurn Wilkins
    $ 816.99 - $ 816.99
    $ 816.99
    $ 816.99 - $ 816.99
    $ 816.99

    The 975XL Reduced Pressure Principle Backflow Assembly is used on non-potable water applications for high health hazard protection from both backsi...

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    $ 816.99 - $ 816.99
    $ 816.99
    $ 816.99 - $ 816.99
    $ 816.99
  • Sold out

    Zurn Wilkins 1-975XLS 1" 975XL Reduced Pressure Assembly w/ Bronze Wye Strainer (Discontinued)

    Zurn Wilkins
    $ 947.99 - $ 947.99
    $ 947.99
    $ 947.99 - $ 947.99
    $ 947.99

    The Zurn Wilkins 975XL Reduced Pressure Principle Backflow Preventer provides high hazard protection for non-potable water applications. The wye p...

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    $ 947.99 - $ 947.99
    $ 947.99
    $ 947.99 - $ 947.99
    $ 947.99
    Sold out

  • Zurn 1-975XL3 1" Reduced Pressure Principle Backflow Preventer

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 983.99
    $ 983.99 - $ 983.99
    $ 983.99

    The Zurn Wilkins 975XL3 Reduced Pressure Principle Backflow Assembly provides high hazard protection against backsiphonage and backpressure in pota...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 983.99
    $ 983.99 - $ 983.99
    $ 983.99

  • Zurn Wilkins 34-975XL 3/4" Reduced Pressure Principle Backflow Preventor

    Zurn Wilkins
    $ 768.99 - $ 768.99
    $ 768.99
    $ 768.99 - $ 768.99
    $ 768.99

    The Zurn Wilkins 975XL Reduced Pressure Principle Backflow Preventer provides high hazard protection for non-potable water applications. The wye p...

    View full details
    $ 768.99 - $ 768.99
    $ 768.99
    $ 768.99 - $ 768.99
    $ 768.99

  • Zurn Wilkins 34-975XL2 3/4" 975XL2 Reduced Pressure Principle Assembly (Lead Free)

    Zurn Wilkins
    $ 1,077.99 - $ 1,077.99
    $ 1,077.99
    $ 1,077.99 - $ 1,077.99
    $ 1,077.99

    Spec Sheet   Install Manual The Zurn Wilkins 975XL2 Reduced Pressure Principle Backflow Preventer provides high hazard protection for potable wa...

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    $ 1,077.99 - $ 1,077.99
    $ 1,077.99
    $ 1,077.99 - $ 1,077.99
    $ 1,077.99

  • Zurn 1" 375 RP Ball Vlv NPT Top Access Lead Free Red Pressure Principle Backflow Preventer

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 983.99
    $ 983.99 - $ 983.99
    $ 983.99

    The Zurn Wilkins 375XL Reduced Pressure Principle Backflow Preventer provides high hazard protection for potable water applications. The EZSwap Pr...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 983.99
    $ 983.99 - $ 983.99
    $ 983.99
  • Sold out

    Zurn 1-975XL2 1" Reduced Pressure Principle Backflow Preventer No Lead

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,139.99
    $ 1,139.99 - $ 1,139.99
    $ 1,139.99

    The 975XL2 Reduced Pressure Principle Assembly is used in high health hazard, potable water applications for protection from both backsiphonage and...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,139.99
    $ 1,139.99 - $ 1,139.99
    $ 1,139.99
    Sold out
  • Sold out

    Zurn Wilkins 34-375XL 3/4" 375 Reduced Pressure Principle Backflow Preventer

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 929.99
    $ 929.99 - $ 929.99
    $ 929.99

    375 Reduced Pressure Principle Backflow Assembly Spec Sheet The 375 Reduced Pressure Principle Backflow Assembly is utilized where a potential hig...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 929.99
    $ 929.99 - $ 929.99
    $ 929.99
    Sold out
  • Sold out

    Zurn 1/2" 975 Reduced Pressure Principle Backflow Preventer Lead Free

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,031.99
    $ 1,031.99 - $ 1,031.99
    $ 1,031.99

    The Zurn Wilkins 975XL2 Reduced Pressure Principle Backflow Preventer provides high hazard protection for potable water applications. The wye patte...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,031.99
    $ 1,031.99 - $ 1,031.99
    $ 1,031.99
    Sold out

  • Zurn Wilkins 4-375AST 4" 375 Reduced Pressure Principle Backflow Preventer with Stainless Steel Body

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 6,721.99
    $ 6,721.99 - $ 6,721.99
    $ 6,721.99

    375 Reduced Pressure Principle Backflow Assembly Spec Sheet The 375 Reduced Pressure Principle Backflow Assembly is utilized where a potential hig...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 6,721.99
    $ 6,721.99 - $ 6,721.99
    $ 6,721.99

  • Zurn Wilkins 12-375XL 1/2" 375 Reduced Pressure Principle Backflow Preventer

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 910.99
    $ 910.99 - $ 910.99
    $ 910.99

    The Zurn Wilkins 375XL Reduced Pressure Principle Backflow Preventer provides high hazard protection for potable water applications. The EZSwap Pr...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 910.99
    $ 910.99 - $ 910.99
    $ 910.99

  • Zurn 3-375AST 3" Reduced Pressure Principle Backflow Preventer with Stainless Steel Body

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 6,474.99
    $ 6,474.99 - $ 6,474.99
    $ 6,474.99

    The 375AST Reduced Pressure Principle Backflow Assembly is utilized in high hazard applications for all applications and market segments, protectin...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 6,474.99
    $ 6,474.99 - $ 6,474.99
    $ 6,474.99

  • Zurn Wilkins - 2-975XL2 2" 975XL2 Reduced Pressure Principle Assembly (Lead Free)

    Zurn Wilkins
    $ 2,212.99 - $ 2,212.99
    $ 2,212.99
    $ 2,212.99 - $ 2,212.99
    $ 2,212.99

    The 975XL2 Reduced Pressure Principle Assembly is used in high health hazard, potable water applications for protection from both backsiphonage and...

    View full details
    $ 2,212.99 - $ 2,212.99
    $ 2,212.99
    $ 2,212.99 - $ 2,212.99
    $ 2,212.99
  • Sold out

    Zurn Wilkins 3" 375A Flanged NRS Reduced Pressure Principle Assembly

    Zurn Wilkins
    $ 5,917.99 - $ 5,917.99
    $ 5,917.99
    $ 5,917.99 - $ 5,917.99
    $ 5,917.99

      The Zurn Wilkins 375A Reduced Pressure Principle Backflow Preventer provides high hazard protection for all market segments. The grooved, epoxy...

    View full details
    $ 5,917.99 - $ 5,917.99
    $ 5,917.99
    $ 5,917.99 - $ 5,917.99
    $ 5,917.99
    Sold out

  • Zurn Wilkins 112-375XL 1-1/2" 375 Reduced Pressure Principle Backflow Preventer

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,727.99
    $ 1,727.99 - $ 1,727.99
    $ 1,727.99

    375 Reduced Pressure Principle Backflow Assembly Spec Sheet The 375 Reduced Pressure Principle Backflow Assembly is utilized where a potential hig...

    View full details
    $ 0.00 - $ 0.00
    $ 0.00
    $ 1,727.99
    $ 1,727.99 - $ 1,727.99
    $ 1,727.99
  • Sold out

    Zurn Wilkins 34-70XLDUC 3/4" 70XL Pressure Reducing Valve with Double Union FNPT Connection and FC (Cop/ Sweat) Union Connection

    Zurn Wilkins
    $ 257.99 - $ 257.99
    $ 257.99
    $ 257.99 - $ 257.99
    $ 257.99

    The 70XL Pressure Reducing Valve is a contractor favorite, providing a variety of residential and commercial customers with extreme stability, rugg...

    View full details
    $ 257.99 - $ 257.99
    $ 257.99
    $ 257.99 - $ 257.99
    $ 257.99
    Sold out
  • Sold out

    Zurn Wilkins 34-NR3XLDUPEX 3/4 in. NR3XL Pressure Reducing Valve, Double Union Male Barbed PEX Connections

    Zurn Wilkins
    $ 232.99 - $ 232.99
    $ 232.99
    $ 232.99 - $ 232.99
    $ 232.99

    Our time-tested Pressure Reducing Valves are ideal for residential applications that require frequent cleaning of sediment and debris prevent build...

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    $ 232.99 - $ 232.99
    $ 232.99
    $ 232.99 - $ 232.99
    $ 232.99
    Sold out
  • Sold out

    Zurn Wilkins 2-NR3XLDUC 2" NR3XL Pressure Reducing Valve with Double Union FNPT Copper Sweat Union Connection

    Zurn Wilkins
    $ 1,387.99 - $ 1,387.99
    $ 1,387.99
    $ 1,387.99 - $ 1,387.99
    $ 1,387.99

    Our time-tested Pressure Reducing Valves are ideal for residential applications that require frequent cleaning of sediment and debris prevent build...

    View full details
    $ 1,387.99 - $ 1,387.99
    $ 1,387.99
    $ 1,387.99 - $ 1,387.99
    $ 1,387.99
    Sold out
  • Sold out

    Zurn Wilkins 34-350XL 3/4" 350XL Double Check Backflow Preventer

    Zurn Wilkins
    $ 448.99 - $ 448.99
    $ 448.99
    $ 448.99 - $ 448.99
    $ 448.99

    The 350XL Double Check Valve Assembly is used in low health hazard, potable water applications for protection against both back siphonage and backp...

    View full details
    $ 448.99 - $ 448.99
    $ 448.99
    $ 448.99 - $ 448.99
    $ 448.99
    Sold out
  • Sold out

    Zurn Wilkins 2-600XL 2" 600XL Pressure Reducing Valve

    Zurn Wilkins
    $ 1,552.99 - $ 1,552.99
    $ 1,552.99
    $ 1,552.99 - $ 1,552.99
    $ 1,552.99

    The 600XL Pressure Reducing Valve handles sandy, debris-laden water systems for high-flow capacity in residential, commercial, and new construction...

    View full details
    $ 1,552.99 - $ 1,552.99
    $ 1,552.99
    $ 1,552.99 - $ 1,552.99
    $ 1,552.99
    Sold out

Before installing, check your local water-utility or code requirements—many jurisdictions mandate annual testing or specific assembly types based on flow, hazard level or chemical injection. Choose the correct device, install it properly (above grade or per elevation specs), and test or maintain it regularly to ensure protection long-term.

Browse through the collection to find the right size, type and brand for your project—then install with confidence knowing your potable supply is locked down.

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