Choosing the right air gap backflow preventer helps protect drinking water from contamination and keeps your plumbing compliant with local codes. The following products are commonly used to create a drain line separation from the potable supply, reducing cross-connection risk in residential and commercial settings. This guide highlights five well-regarded options with different sizes and installation styles to fit horizontal or vertical configurations.
Summary of selected products:
- Wilkins AG-4 Lead-Free Water Hammer Arrestor with 1″ MNPT — Lead-free, RP backflow compatibility
- WATTS 0881399 1/4 to 1/2 inch 909 AGA Air Gap — Compact, US-manufactured options
- Zurn AG-5 – Air Gap Fitting, Blue — Large-size air gap fitting for RP connections
- WHK Hose Bib Backflow Preventer Vacuum Breaker — 3/4″ outdoor, anti-siphon design
- WATTS 909AGF AIR Gap Iron BACKFLOW Preventer 2IN — Iron construction for robust installs
Wilkins AG-4 Lead-Free Water Hammer Arrestor
The Wilkins AG-4 is designed for compatibility with multiple RP backflow preventers, including the 975XL series. It provides a means to attach a drain line to an RP unit and helps prevent cross connections between the drain and the potable supply. This lead-free option is suitable for horizontal or vertical installations, supporting reliable plumbing performance in various backflow control scenarios.
WATTS 0881399 1/4 to 1/2 Inch 909 AGA Air Gap
The Watts 909 AGA air gap unit offers a compact solution for creating a vertical separation between the drain and potable lines. This model emphasizes straightforward installation and is suitable for small-to-medium projects. Its product traits highlight brand reliability and origin in the United States, making it a practical choice for typical residential installations.
Zurn AG-5 – Air Gap Fitting, Blue
The Zurn AG-5 air gap fitting provides a 1-1/4″ to 2″ size range and is designed to connect RP backflow units with a dedicated drain line. This blue, heavy-duty fitting helps prevent cross connections between the drain and potable supply and is compatible with RP-style backflow prevention assemblies in larger installations.
WHK Hose Bib Backflow Preventer Vacuum Breaker
The WHK backflow preventer is designed for outdoor use where standard hose bib connections are common. Made from solid brass, it features a 3/4-inch inlet and outlet with a self-draining vacuum breaker. It meets several safety standards and is suitable for garden hoses, RV hookups, and sillcocks, offering anti-siphon protection and manual draining to prevent freezing.
WATTS 909AGF Air Gap Iron Backflow Preventer 2IN
The Watts 909AGF is a robust iron backflow preventer designed for larger installations. With a 2-inch size, this unit delivers a substantial air gap for preventing back-siphonage into the potable water system. Its threaded mounting supports secure attachment in commercial or heavy-duty residential settings, ensuring long-term reliability in backflow prevention.
Buying Guide
- Size and compatibility: Ensure the air gap or RP backflow device matches your pipe diameter and the backflow preventer model you are using.
- Material and durability: Brass and iron constructions offer strong corrosion resistance for outdoor or high-use environments; lead-free options reduce contamination risk.
- Installation orientation: Some units support horizontal and vertical mounting; verify orientation guidelines in product specs to prevent improper operation.
- Standards and testing: Look for devices that meet ASSE, CSA, and ANSI/NSF standards for backflow prevention and vacuum breaking.
- Maintenance and drainage: Consider units with accessible drain connections and features like self-draining vacuum breakers to minimize freezing and maintenance needs.
- Access and replacement: Choose models with readily available replacement parts and clear installation instructions for DIY or professional setups.
- Application context: Outdoor hose connections, irrigation systems, and indoor RP backflow assemblies may require different gap sizes or fittings; match product capabilities to your use case.