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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.

  • Sold out

    Apollo - Bronze FIP Pressure Vacuum Breaker 4A Series A2F

    Apollo
    $ 104.02 - $ 104.95
    $ 104.02 - $ 104.95
    $ 104.02 - $ 104.95
    $ 104.02

    This vacuum breaker prevents contamination of the potable water due to back siphon-age. A integrated freeze protection relief valve serves to reduc...

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    $ 104.02 - $ 104.95
    $ 104.02 - $ 104.95
    $ 104.02 - $ 104.95
    $ 104.02
    Sold out
  • Sold out

    Febco - 765-QT75 - 3/4 in. 765 Backflow Preventer

    Febco
    $ 116.62 - $ 116.62
    $ 116.62
    $ 116.62 - $ 116.62
    $ 116.62

    Spec Sheet   Install Manual New Version Series 765 Pressure Vacuum Breakers Size: 1/2" - 2" (15mm - 50mm) The FEBCO Series 765 Pressure Vacuum ...

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    $ 116.62 - $ 116.62
    $ 116.62
    $ 116.62 - $ 116.62
    $ 116.62
    Sold out
  • Sold out

    Apollo - Backflow Preventer, Reduced Pressure, Bronze with Ball Valves and SAE Test Cocks

    Apollo
    $ 274.00 - $ 327.14
    $ 274.00 - $ 327.14
    $ 274.00 - $ 327.14
    $ 274.00

    This vacuum breaker prevents contamination of the potable water due to back siphon-age. A integrated freeze protection relief valve serves to reduc...

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    $ 274.00 - $ 327.14
    $ 274.00 - $ 327.14
    $ 274.00 - $ 327.14
    $ 274.00
    Sold out

  • Watts 0125572 3/4" LF25AUB-Z3 Pressure Reducing Valve (Press) Lead Free

    Watts Water Technologies
    $ 223.36 - $ 223.36
    $ 223.36
    $ 223.36 - $ 223.36
    $ 223.36

    Specs Installation   Maximum Working Pressure: 300psi (21 bar)Adjustable Reduced Pressure Range: 25 to 75psi (172 to 517 kPa)Standard Pressure ...

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    $ 223.36 - $ 223.36
    $ 223.36
    $ 223.36 - $ 223.36
    $ 223.36
  • Sold out

    Watts - 34-LF009M3-QT - Backflow System Low Pressure, 3/4" FIP

    Watts Water Technologies
    $ 483.32 - $ 483.32
    $ 483.32
    $ 483.32 - $ 483.32
    $ 483.32

    This 3/4 inch reduced pressure zone assembly is designed to prevent the flow of polluted water from entering into the potable water supply due to...

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    $ 483.32 - $ 483.32
    $ 483.32
    $ 483.32 - $ 483.32
    $ 483.32
    Sold out

  • Febco - 860U-QT-FS 3/4 - 3/4 IN Bronze Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff, Union Ball Valves, Small Diameter, Backflow Flood Sensor

    Febco
    $ 0.00 - $ 0.00
    $ 0.00
    $ 464.97
    $ 464.97 - $ 464.97
    $ 464.97

    3/4 IN Bronze Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff, Union Ball Valves, Small Diameter, Backflow Flood Sensor Thi...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 464.97
    $ 464.97 - $ 464.97
    $ 464.97

  • Zurn Wilkins 34-720A 3/4 Inch Pressure Vacuum Breaker Assembly

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 147.99
    $ 147.99 - $ 147.99
    $ 147.99

    Our Pressure Vacuum Breaker protects against back siphonage in high health hazard, non-potable residential and commercial irrigation applications. ...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 147.99
    $ 147.99 - $ 147.99
    $ 147.99

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

    Zurn Wilkins
    $ 732.99 - $ 732.99
    $ 732.99
    $ 732.99 - $ 732.99
    $ 732.99

    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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    $ 732.99 - $ 732.99
    $ 732.99
    $ 732.99 - $ 732.99
    $ 732.99

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

    Zurn Wilkins
    $ 1,025.99 - $ 1,025.99
    $ 1,025.99
    $ 1,025.99 - $ 1,025.99
    $ 1,025.99

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

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    $ 1,025.99 - $ 1,025.99
    $ 1,025.99
    $ 1,025.99 - $ 1,025.99
    $ 1,025.99

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

    Zurn Wilkins
    $ 0.00 - $ 0.00
    $ 0.00
    $ 884.99
    $ 884.99 - $ 884.99
    $ 884.99

    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
    $ 884.99
    $ 884.99 - $ 884.99
    $ 884.99
  • 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
    $ 244.99 - $ 244.99
    $ 244.99
    $ 244.99 - $ 244.99
    $ 244.99

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

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    $ 244.99 - $ 244.99
    $ 244.99
    $ 244.99 - $ 244.99
    $ 244.99
    Sold out
  • Sold out

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

    Zurn Wilkins
    $ 221.99 - $ 221.99
    $ 221.99
    $ 221.99 - $ 221.99
    $ 221.99

    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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    $ 221.99 - $ 221.99
    $ 221.99
    $ 221.99 - $ 221.99
    $ 221.99
    Sold out
  • Sold out

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

    Zurn Wilkins
    $ 427.99 - $ 427.99
    $ 427.99
    $ 427.99 - $ 427.99
    $ 427.99

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

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    $ 427.99 - $ 427.99
    $ 427.99
    $ 427.99 - $ 427.99
    $ 427.99
    Sold out
  • Sold out

    Zurn Wilkins 34-NR3XLDU 3/4" Lead Free Water Pressure Reducing Valve w/ Integral By-Pass Check Valve

    Zurn Wilkins
    $ 221.99 - $ 221.99
    $ 221.99
    $ 221.99 - $ 221.99
    $ 221.99

    Ideal for use where lead free valves are required. Designed for installation on potable water lines to reduce high inlet pressure to a lower outle...

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    $ 221.99 - $ 221.99
    $ 221.99
    $ 221.99 - $ 221.99
    $ 221.99
    Sold out
  • Sold out

    Zurn Wilkins 34-950XLT2 3/4" Wilkins 950XLT2 Double Check Valve Assembly (Lead Free)

    Zurn Wilkins
    $ 462.99 - $ 462.99
    $ 462.99
    $ 462.99 - $ 462.99
    $ 462.99

    The Zurn Wilkins 950XLT2 Double Check Valve Assembly provides top access check covers. Suitable for below grade installation in standard valve box...

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    $ 462.99 - $ 462.99
    $ 462.99
    $ 462.99 - $ 462.99
    $ 462.99
    Sold out
  • Sold out

    Zurn Wilkins 34-600XL 600XL FNPT Union x FNPT Pressure Reducing Valve (Lead Free)

    Zurn Wilkins
    $ 318.99 - $ 318.99
    $ 318.99
    $ 318.99 - $ 318.99
    $ 318.99

    Zurn Wilkins Model 34-600XL 3/4" Water Pressure Reducing Brass Valve with Integral By-pass Check Valve and Strainer, FNPT Union x FNPT, Lead Free ...

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    $ 318.99 - $ 318.99
    $ 318.99
    $ 318.99 - $ 318.99
    $ 318.99
    Sold out

  • Watts LF009M3-QT-S 3/4 3/4 IN Lead Free Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff Valves, Bronze Strainer (Discontinued)

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 579.00
    $ 579.00 - $ 579.00
    $ 579.00

    3/4 IN Lead Free Reduced Pressure Zone Backflow Preventer Assembly, Quarter Turn Shutoff Valves, Bronze Strainer Lead Free: YES 0122695 This 3/4 i...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 579.00
    $ 579.00 - $ 579.00
    $ 579.00

  • Watts LFN45BM1-U-S 3/4 3/4 IN Lead Free Water Pressure Reducing Valve, Solder Union x FPT, Adjust 25-75 psi, Max Work 400 psi 0009480

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 178.98
    $ 178.98 - $ 178.98
    $ 178.98

    3/4 IN Lead Free Water Pressure Reducing Valve, Solder Union x FPT, Adjust 25-75 psi, Max Work 400 psi 0009480 Lead Free: YES   This 3/4 inch lead...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 178.98
    $ 178.98 - $ 178.98
    $ 178.98

  • Watts - 3/4-LF860-QT RP - 3/4" RPZ Lead Free 860 Series Reduced Pressure Zone Assy #0683001

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 613.12
    $ 613.12 - $ 613.12
    $ 613.12

    This 3/4 inch lead free reduced pressure zone backflow preventer assembly is designed to prevent the reverse flow of high hazard (toxic) fluids fo...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 613.12
    $ 613.12 - $ 613.12
    $ 613.12

  • Watts - LF007M3-QT-FZ - 3/4 - 3/4 In Lead Free Double Check Valve Backflow Preventer Assembly, Quarter Turn Shutoff, Single Top Entry 0063231

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 403.89
    $ 403.89 - $ 403.89
    $ 403.89

    Series LF007 Double Check Valve assemblies are installed at referenced cross-connections to prevent the backflow of polluted water into the potable...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 403.89
    $ 403.89 - $ 403.89
    $ 403.89

  • Watts LFN55BM1 U 3/4 3/4 IN Lead Free Water Pressure Reducing Valve, NPT Thread Union x NPT Female, Max Work 400 psi, Adjust 25-75 psi - 009589

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 170.93
    $ 170.93 - $ 170.93
    $ 170.93

    3/4 IN Lead Free Water Pressure Reducing Valve, NPT Thread Union x NPT Female, Max Work 400 psi, Adjust 25-75 psi 0009589 Lead Free: YES This 3/4 ...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 170.93
    $ 170.93 - $ 170.93
    $ 170.93
  • Sold out

    Watts LFN45BM1-U 3/4 3/4 IN Lead Free Water Pressure Reducing Valve, NPT Union x FPT, Adjust 25-75 psi, Max Work 400 psi 0009478

    Watts Water Technologies
    $ 0.00 - $ 0.00
    $ 0.00
    $ 171.53
    $ 171.53 - $ 171.53
    $ 171.53

    3/4 IN Lead Free Water Pressure Reducing Valve, NPT Union x FPT, Adjust 25-75 psi, Max Work 400 psi 0009478 Lead Free: YES   This 3/4 inch lead fr...

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    $ 0.00 - $ 0.00
    $ 0.00
    $ 171.53
    $ 171.53 - $ 171.53
    $ 171.53
    Sold out

  • Febco Poppet Assembly Kit for 1/2", 3/4" 765 Pressure Vacuum Breaker

    Febco
    $ 26.08 - $ 26.08
    $ 26.08
    $ 26.08
    $ 26.08 - $ 26.08
    $ 26.08

    Febco: 1/2" - 3/4" - Poppet Assembly for a 765 Pressure Vacuum Breaker

    $ 26.08 - $ 26.08
    $ 26.08
    $ 26.08
    $ 26.08 - $ 26.08
    $ 26.08

  • Febco 3/4" RPZ Principal Assembly (Top Access) ¾” 860-QT-FS RP F1312 860-QT-FS 3/4

    Febco
    $ 489.99 - $ 489.99
    $ 489.99
    $ 501.09
    $ 501.09 - $ 501.09
    $ 501.09

    This 3/4 inch reduced pressure zone backflow preventer assembly prevents the reverse flow of high hazard (toxic) fluids found in the water from en...

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    $ 489.99 - $ 489.99
    $ 489.99
    $ 501.09
    $ 501.09 - $ 501.09
    $ 501.09

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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