Double check valve testing across New Jersey by a certified specialist. Accurate testing, documentation, and municipal paperwork. Call 201-687-1292.
A double check valve assembly — often abbreviated DCVA or simply called a double check — is one of the most common backflow preventers in use. It consists of two independently operating check valves in series, so that if one fails to seal, the second still protects the water supply. Double check assemblies are typically used for lower-hazard connections, where a backflow event would be a nuisance or aesthetic concern rather than a health hazard — common examples include certain irrigation systems, fire-suppression lines, and some commercial connections. JC Backflow Inspections LLC provides certified double check valve testing throughout New Jersey.
While a double check is simpler than an RPZ, it still relies on seals and springs that wear over time, and the only way to know both check valves still hold is to test them. That is why water authorities require double check assemblies to be tested on a regular schedule, usually annually, by a certified professional. A device that quietly develops a leaking check valve no longer provides the redundant protection it was installed for.
A certified tester isolates the assembly and connects calibrated gauges to its test cocks, then measures each check valve independently to confirm both hold pressure within specification. The procedure is recognized and specific to double check assemblies. We record the make, model, size, serial number, location, measured results, and a clear pass or fail outcome. If the assembly passes, we submit the certification to your water authority; if it fails, we explain which check valve is at fault and guide you through a rebuild or replacement, then retest.
Even though double check assemblies typically guard lower-hazard connections, they are still part of the cross-connection control program and still legally required to be tested and certified where they are installed. A fire-line double check that fails, for instance, can put a property out of compliance and trigger notices and fines just as surely as a failed high-hazard device. Keeping your double check assemblies tested protects the water supply’s redundancy and keeps your property in good standing. Backflow testing and reporting requirements may vary by municipality, water authority, property type, and device type, and we handle the documentation accordingly.
Double check assemblies are widespread. Commercial buildings, retail centers, office parks, and warehouses frequently have them on fire-suppression and irrigation lines. Apartment complexes and other multi-family properties often do as well, and many homes with lawn irrigation systems have a double check or a related lower-hazard device. If your property has irrigation or a fire line with a backflow preventer, there is a good chance it includes a double check assembly that needs periodic testing.
Because we specialize only in backflow, we test double check assemblies efficiently and document them accurately, and we recognize the failure patterns specific to these devices. We also handle rebuilds and certification, so a failed double check can return to compliance with one accountable team rather than several vendors.
We offer same-day service when schedules allow, emergency appointments, free estimates, and the municipal paperwork handled for you. You work directly with a certified specialist and owner Jennifer Castro’s small team, with clear communication from scheduling through certification.
The defining feature of a double check assembly is its built-in redundancy: two independent check valves, so that protection continues even if one valve develops a problem. That redundancy is genuinely valuable, but it can also create a false sense of security if testing is neglected. Here is the catch — if the first check valve fails silently and goes unnoticed because the second is still holding, the device is now operating with no margin of safety. Should the second valve then fail, there is nothing left to protect the supply. Annual testing exists precisely to catch that first failure before the second one matters, restoring the redundancy the device was installed to provide. This is why a “working” double check is not the same as a tested one; only a calibrated test confirms both valves are independently holding. For irrigation and fire-line applications where double checks are common, keeping that redundancy intact is a simple, inexpensive safeguard, and it is exactly what our annual testing verifies. We document both valves’ performance so you have proof the protection is fully intact, not just partially.
What is a double check valve assembly? It is a backflow preventer with two independent check valves in series, providing redundant protection — if one valve fails to seal, the other still guards the supply. Double checks are commonly used on lower-hazard connections such as some irrigation and fire-suppression lines.
How is a double check different from an RPZ? A double check has two check valves and is used for lower-hazard connections, while an RPZ adds a relief valve and is used for high-hazard connections where contamination could be dangerous. The testing procedures and risk levels differ, which is why the correct device type matters for your specific connection.
How often does a double check assembly need testing? Most New Jersey authorities require annual testing by a certified professional. Backflow testing and reporting requirements may vary by municipality, water authority, property type, and device type, so we confirm your schedule and remind you before each test is due.
What if one of the check valves fails? We identify which check valve is at fault and guide you through a rebuild — replacing the worn internal components — or a replacement if needed, then retest and re-certify. Because we handle all these steps, your device returns to compliance quickly.
Do homes have double check assemblies? Many homes with lawn irrigation systems have a double check or a related lower-hazard backflow device that requires periodic testing where a cross-connection exists. If you received a notice or have an irrigation system, call us and we will confirm your device type and what is required.