Double Check Valve Assembly (DCVA)
A Double Check Valve Assembly (DCVA) uses two independent, spring-loaded check valves in series to prevent irrigation water from flowing backward into your potable water supply. It's the standard backflow prevention choice for low-hazard residential irrigation systems, where the risk of contamination is relatively low compared to systems using fertilizer injection or other chemical additives. Shop professional-grade DCVA assemblies sized to protect your system and keep it compliant with local backflow requirements.
Double Check Valve Assembly (DCVA)
A DCVA works on a simple principle: two independent check valves, connected in series, each allow water to flow in one direction only — toward the irrigation system — and close automatically if pressure ever reverses. Because there are two independent valves rather than one, the assembly still provides protection even if a single check valve fails, which is part of why it's an accepted standard for lower-risk applications rather than requiring the more complex mechanism of an RPZ.
DCVAs are specifically rated for low-hazard systems, meaning the water in the irrigation line poses a health risk if it siphons backward, but not one severe enough to require the additional protection of an assembly that actively vents to atmosphere. A typical residential sprinkler or drip system without fertilizer injection or other chemical feed usually falls into this low-hazard category, which is why DCVA is the most common backflow assembly installed on residential irrigation.
Installation location matters for a DCVA the same way it does for any backflow assembly: it needs to sit downstream of the water meter and upstream of the irrigation system, in a location that's accessible for testing and maintenance — many jurisdictions require periodic testing of backflow assemblies, so a DCVA buried or boxed in without easy access can turn a routine test into an unnecessarily difficult one.
If a DCVA fails testing or starts showing signs of wear — a valve that won't fully seal, or visible corrosion — Parts & Repair Kits cover common replacement components. For systems with a higher hazard classification, such as those using fertilizer injection or connected to a non-potable source, a Reduced Pressure Zone Assembly (RPZ) provides a higher level of protection than a DCVA is rated for.
The Learn HUB has guides for understanding hazard classifications and confirming which backflow assembly your local code requires.
