Yes. The right assembly is determined by the hazard level of what is downstream, whether back-pressure is possible in addition to back-siphonage, installation location, and local water authority requirements — not by preference or price.

What We Evaluate

  • Hazard level. The primary factor. Irrigation with fertilizer injection, a boiler with treated water, or a commercial process connection are high-hazard and require an RPZ assembly. A simple sprinkler system with no chemical injection may allow a lower-tier device.
  • Back-pressure vs. back-siphonage. Pressure vacuum breakers protect against siphonage only. If downstream pressure could ever exceed supply pressure — a pump, a boiler, an elevated tank — you need an assembly rated for back-pressure.
  • Installation location. RPZ assemblies must be above grade with drainage for relief discharge. PVBs must sit above the highest downstream outlet. These constraints sometimes decide the answer.
  • Freeze exposure. A real consideration in New Mexico for outdoor irrigation assemblies.
  • Local requirements. The water authority has the final say, and requirements vary by jurisdiction and application.

The Types

RPZ assembly — highest protection, two checks plus a relief valve, required for high-hazard. Double check valve assembly — two checks in series, for lower-hazard connections. Pressure vacuum breaker — common on irrigation, siphonage protection only. Atmospheric vacuum breaker — simplest, for individual hose bibs and specific fixtures.

Residential vs. Commercial

Residential applications are usually irrigation, boilers, and pools. Commercial properties face broader requirements and more active enforcement, with testing schedules the water authority tracks.

Two Things We Flag During Selection

Winterization planning for outdoor assemblies, since a hard freeze cracks an unprotected one. And whether you have an expansion tank — a backflow preventer creates a closed system, and without one your water heater relief valve will start weeping.

Contact B. Carlson about backflow prevention in Albuquerque.