Backflow prevention is essential for protecting potable water supplies. This guide compares five top double check valve assemblies to help plumbers, facility managers, and homeowners choose the right model for non-health hazard applications. Each option is evaluated for best-use scenarios, ease of maintenance, and notable limitations.
The top picks below are best for: residential irrigation and service line protection, small commercial setups, outdoor and exposed installations, retrofit projects with limited space, and configurations requiring quick serviceability. A quick-reference summary follows the introduction to help you compare at a glance.
Product Comparison Snapshot
| Product | Best For | Key Benefit | Limitation |
|---|---|---|---|
| Febco LF850 Series 2″ Double Check Valve | Small to mid-size commercial or service-line protection | Lead-free body with freeze sensor and modular design | Higher complexity may require professional installation |
| Watts 007 Series 1-1/2″ Double Check | Bronze-bodied systems with compact, easy maintenance | Top entry, replaceable parts, integrated freeze sensor option | Bronze materials may be pricier than other blends |
| Zurn Wilkins 2-350XL 2″ | Easy retrofit in mid-size piping with streamlined maintenance | EZSwap pressure vessel and top-mounted test cocks | May require careful sizing for high-flow projects |
| Watts LF007 Series 1″ Lead-Free Bronze | Lead-free, compact assemblies for installations with space limits | Inline serviceable, NPT connections, modular design | Smaller size may limit high-flow applications |
| Zurn Wilkins 34-350 3/4″ | Irrigation and service-entry protection in tight spaces | Serviceable off-line with flush options | Smaller flow capacity; verify system requirements |
Febco LF850 Series 2″ Double Check Valve
The Febco LF850 is a lead-free copper silicon alloy double check valve designed for non-health hazard applications in continuous-pressure piping. It protects potable water by preventing backflow due to back-siphonage or backpressure. The assembly features NPT connections, quarter-turn shutoffs, top-mounted test cocks, two independent check modules, and captured springs. A freeze sensor is included and compatible with SentryPlus Alert, with an optional kit for expanded monitoring.
Best for: facilities needing a robust, lead-free option with temperature monitoring to guard against freezing conditions. This is a strong choice for service lines and cross-connections in commercial or residential installations where backflow protection is a priority and freeze risk exists.
Limitations: The more modular design and multiple components can increase initial setup complexity. Ensure compatible with your existing piping layout and confirm freeze-sensor compatibility for your system.
Watts 007 Series 1-1/2″ Double Check Valve
The Watts 007 Series uses a bronze body with a compact modular design and a top-mounted ball valve for reliable operation. It is designed to meet national plumbing codes for non-potable applications such as irrigation and firelines, making it suitable for outdoor and exposed installations. A freeze sensor connection kit is available to enable SentryPlus Alert monitoring with wireless reporting.
Best for: installations needing a durable bronze body and an easy-to-inspect, top-entry configuration. This model is ideal for outdoor irrigation setups or installations where space is available for a modular turn-key assembly.
Limitation: Bronze options can be more expensive than some plastic or simpler alloy bodies. Confirm flow requirements to ensure it matches your system’s needs.
Feeligivin 34-350 3/4″ Double Check Backflow Preventer
This double check backflow preventer uses two independently operating spring-loaded check valves to guard against both backpressure and backsiphonage. It emphasizes easy maintenance with a service design that allows removal and replacement of internal components as a complete unit, without detaching the valve body. The cast bronze main body is paired with UV-resistant housing and stainless hardware for outdoor durability.
Best for: outdoor irrigation or exposed piping where quick maintenance and straightforward servicing are priorities. The easy-service design helps minimize downtime during preventive maintenance or repairs.
Warning: As with all outdoor devices, verify environmental exposure and ensure the unit’s size aligns with your line’s diameter and pressure requirements.
Zurn Wilkins 2-350XL 2″ Double Check Backflow Preventer
The 2-350XL model features a top-mounted test cock arrangement and an EZSwap pressure vessel, designed to reduce repair time and costs. A flush tool is included to simplify line flushing, saving installation time. This unit is well-suited for mid-size piping where quick servicing and straightforward maintenance are valuable.
Best for: facilities needing efficient maintenance and simplified installation with a reliable, top-entry style. It’s a good candidate when time savings during servicing are a priority.
Limitation: Larger models require adequate space for tool access and service; verify clearance around the valve during installation.
Watts LF007 Series 1″ Lead-Free Bronze Double Check
This lead-free bronze double check valve assembly combines NPT connections with quarter-turn shutoffs and a modular design for easy upgrades and maintenance. It includes two inline check modules and captured springs to ensure reliable braking of backflow. The unit is designed to comply with plumbing codes for non-health hazard applications.
Best for: projects requiring a high-quality, lead-free bronze option with straightforward inline serviceability and compact footprint, suitable for tight installations.
Limitation: This is a 1″ model; assess your system’s flow demands to confirm adequate capacity for your scenario.
Zurn Wilkins 34-350 3/4″ Double Check Backflow Preventer
The 34-350 3/4″ model emphasizes a serviceable offline design with a flush tool option for quick line flushing and maintenance. It is designed to deliver water savings while providing dependable backflow protection. The unit is compact enough for tight spaces and straightforward to install in residential irrigation or service-line crossings.
Best for: spaces where a compact, offline-serviceable option is required, and where flushing capability helps manage maintenance without full disassembly. Confirm compatibility with existing piping and space constraints.
Buying Guide: Key Considerations for Double Check Backflow Valves
What is your application type?
Non-health hazard applications include irrigation, firelines, and service-line protection. Ensure the model meets local codes and authority requirements for non-potable use.
Material and lead content
Lead-free options (bronze, copper-silicon alloys) help reduce regulatory concerns and meet safety standards. Consider the environment (outdoor vs indoor) when selecting materials for durability.
Size and flow capacity
Match the valve size to your piping diameter and expected flow rate. Smaller 3/4″ and 1″ models suit residential or light commercial, while 2″ models support higher flows in mid-size systems.
Maintenance and serviceability
Look for inline serviceability, replaceable discs and seats, and top-entry access. Quick-flush tools and EZSwap vessels can reduce downtime and labor costs.
Installation environment
Outdoor and exposed installations benefit from UV-resistant housings and corrosion-resistant materials. Ensure freeze protection is available or compatible with monitoring systems if freezing risk exists.
Monitoring and integration
Some models offer freeze sensors and compatibility with monitoring networks (like SentryPlus). Consider whether wireless alerts are desirable for your facility management plan.
Cost and lifecycle considerations
Initial cost should be weighed against maintenance ease, service downtime, and expected service-life. Bronze and copper-silicon alloy bodies often offer longer service life in harsh environments.
FAQ
- What is a double check valve used for?
It provides backflow protection by preventing water from flowing backward into the potable supply due to back-siphonage or backpressure.
- Do these valves require regular testing?
Some configurations require periodic test cocks checks per local codes; verify with your authority having jurisdiction.
- Are lead-free options mandatory in my area?
Many regions require lead-free components for potable systems; check local regulations.
- Can I install these myself, or should I hire a professional?
Installation complexity varies by model and site; consider professional installation for accurate sizing and compliance.
- What is the benefit of a top-entry design?
Top-entry access simplifies servicing and testing without full disassembly of the valve.
- When should I choose a bronze vs copper-silicon alloy body?
Bronze offers durability and corrosion resistance in many environments; copper-silicon alloys are common for lead-free, potable-water compliance.