Febco Backflow Preventers: Models and Applications

Febco is a manufacturer of backflow prevention assemblies whose product line spans residential, commercial, and industrial applications across the United States. The brand, operating under Watts Water Technologies, produces devices tested and listed under the USC Foundation for Cross-Connection Control and Hydraulic Research program — a prerequisite for approval under the plumbing codes adopted by most US water authorities. This page covers the major Febco model families, their mechanical classifications, applicable hazard ratings, and the regulatory and installation contexts in which each model type is deployed. Navigating this product landscape requires matching device type, pressure rating, and hazard classification to the specific cross-connection being controlled, a determination that falls within the scope of a licensed backflow prevention tester or certified plumber.

Definition and scope

Febco backflow preventers are mechanical assemblies engineered to interrupt reverse flow events — whether caused by backpressure or backsiphonage — at cross-connection points in potable water distribution systems. The assemblies are listed by the Foundation for Cross-Connection Control and Hydraulic Research at the University of Southern California (USC FCCCHR), the primary third-party listing authority referenced by water utilities and code enforcement agencies across the United States.

Device selection within the Febco catalog is governed by hazard classification — a system codified in the USC Manual of Cross-Connection Control and reinforced by standards from ASSE International, the standards body that publishes the performance thresholds each assembly type must meet. The two foundational ASSE categories that structure Febco's primary product lines are high-hazard protection (ASSE 1013 for Reduced Pressure Zone assemblies) and low-hazard protection (ASSE 1015 for Double Check Valve assemblies).

The Febco product line includes four primary device classifications:

  1. Reduced Pressure Zone (RPZ) assemblies — for high-hazard cross-connections where contamination could cause serious health consequences
  2. Double Check Valve (DC) assemblies — for low-hazard cross-connections where contamination risk is limited to non-health-threatening impairment
  3. Pressure Vacuum Breakers (PVB) — for irrigation systems and other non-continuous-pressure applications
  4. Dual Check Valve devices — for residential service protection at low-hazard point-of-use connections

Febco model numbers are structured to indicate both assembly type and pressure class. The 825Y series, for example, designates an RPZ assembly rated for working pressures up to 175 psi, while the 850 series designates a double check valve assembly in a similar pressure range. The 765 series covers pressure vacuum breakers designed for irrigation system use under USC FCCCHR listing conditions.

How it works

RPZ assemblies — the highest-protection class in the Febco catalog — operate through three functional zones: two independently acting check valves and a hydraulically operated relief valve positioned between them. Under normal flow, both check valves remain open and the relief valve remains closed. If downstream pressure rises above supply pressure (backpressure event), or if supply pressure drops below atmospheric (backsiphonage event), the relief valve opens and discharges water to atmosphere, physically preventing contaminated water from migrating upstream. This discharge is the defining operational characteristic of the RPZ and the reason the Uniform Plumbing Code (UPC) and the International Plumbing Code (IPC) require RPZ installation in high-hazard contexts.

Double check valve assemblies use two serially arranged spring-loaded check valves without a relief valve. Each check valve closes independently when downstream pressure meets or exceeds upstream pressure. Because there is no atmospheric vent, double check assemblies are limited to low-hazard applications — they cannot provide the fail-open, discharge-to-atmosphere protection that high-hazard scenarios demand.

Pressure vacuum breakers in the Febco 765 series function by admitting air into the supply line whenever pressure drops below atmospheric, breaking any siphon before contaminated water can reverse direction. PVBs are suitable for irrigation applications but are prohibited on connections subject to backpressure, a constraint enforced by both USC FCCCHR listing conditions and the IPC.

Common scenarios

Febco RPZ assemblies (825Y and related models) are most frequently specified in four installation contexts:

  1. Fire suppression system connections — where chemical additives in sprinkler systems represent a high-hazard cross-connection to the potable supply
  2. Industrial process water connections — where cooling tower chemicals, boiler additives, or process fluids may be present downstream
  3. Irrigation systems with chemical injection — where fertilizer or pesticide injection equipment creates a direct high-hazard cross-connection
  4. Medical and laboratory facilities — where reverse flow could introduce biological or chemical contaminants

Febco double check assemblies (850 series) are deployed on low-hazard commercial irrigation systems without chemical injection, multi-family residential service entries, and auxiliary water supply connections assessed as non-health-threatening under the applicable cross-connection control program administered by the local water utility.

The 765 PVB series is standard equipment on residential and light commercial irrigation systems in jurisdictions where water authority cross-connection control programs — operating under EPA Cross-Connection Control guidelines (EPA Cross-Connection Control Manual) — permit vacuum breaker protection on non-chemical irrigation laterals.

For professionals seeking listed testers qualified to annually test and certify these assemblies, the backflow listings directory indexes certified backflow prevention assembly testers by jurisdiction.

Decision boundaries

Selecting between Febco model families is not discretionary — it is determined by hazard classification, installation geometry, and local authority having jurisdiction (AHJ) requirements. The following boundaries govern device selection:

RPZ vs. Double Check:
The line between RPZ and double check application is drawn at hazard classification. High-hazard cross-connections — defined under USC FCCCHR listing criteria and ASSE 1013 — require RPZ regardless of installer or owner preference. Double check assemblies certified under ASSE 1015 are prohibited on high-hazard applications even if local code does not explicitly enumerate the specific connection type.

PVB limitations:
Pressure vacuum breakers are prohibited where downstream pressure can exceed upstream supply pressure at any time. This eliminates PVBs from booster pump systems, closed-loop systems, and any installation where backpressure is a credible condition. This constraint is structural — it derives from the mechanical operation of the device, not from any discretionary code provision.

Testability requirements:
RPZ and double check assemblies must be field-testable through test cocks, a requirement codified in ASSE 1013 and 1015 respectively. Annual testing by a certified backflow prevention assembly tester (BPAT) is mandated by most water utilities operating cross-connection control programs. PVBs in the Febco 765 series are also testable under ASSE 1020, and annual testing is required by a growing number of municipal authorities. The backflow-directory-purpose-and-scope section of this resource describes how the professional landscape for certified testers is organized nationally.

Installation geometry:
Febco RPZ assemblies require installation above grade in a location where the relief valve discharge port cannot be submerged — submergence would defeat the atmospheric break that defines RPZ protection. Enclosure requirements, minimum clearance dimensions, and drain provisions are specified in local plumbing codes and in Watts/Febco installation documentation filed with USC FCCCHR. The how to use this backflow resource page describes how regulatory framing and device classification information on this site connects to those local authority requirements.

Permit and inspection requirements:
Installation of any Febco testable assembly — RPZ, double check, or PVB — constitutes a regulated plumbing activity requiring a permit from the local building or plumbing authority in virtually all US jurisdictions. Inspection by a licensed plumbing inspector precedes commissioning, and initial field testing by a BPAT is required before the assembly is placed in service under the cross-connection control programs administered by most water utilities under state primacy agency oversight.

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