ASSE Standards for Backflow Prevention Devices

ASSE International publishes the product performance standards that govern how backflow prevention devices are designed, tested, and certified in the United States. These standards define minimum performance thresholds for each device type, determine which assemblies are appropriate for which hazard levels, and form the technical backbone of cross-connection control programs enforced by water utilities and building code authorities. The applicable ASSE standard for a given installation is a prerequisite for compliance with plumbing codes and local water authority requirements. This reference covers ASSE's classification structure, how individual standards function, the scenarios in which specific standards apply, and the boundaries that determine which standard governs a given installation.

Definition and scope

ASSE International (formerly the American Society of Sanitary Engineering) is a standards development organization accredited by the American National Standards Institute (ANSI). Its product performance standards for backflow prevention devices are referenced directly by the Uniform Plumbing Code (UPC) published by IAPMO, the International Plumbing Code (IPC) published by the International Code Council, and NFPA 13 for fire suppression systems. Each standard carries a four-digit number in the 1000 series and specifies:

1. Minimum pressure ratings and differential pressure performance thresholds
2. Head loss limits under defined flow conditions
3. Endurance and cycle testing requirements
4. Materials compatibility with potable water
5. Labeling, marking, and third-party listing obligations

Third-party certification bodies — including NSF International, the International Association of Plumbing and Mechanical Officials (IAPMO R&T), and CSA Group — evaluate devices against ASSE criteria and issue listings that water utilities and inspection authorities use to verify field compliance.

The ASSE 1000-series standards do not cover installation methods or maintenance intervals; those requirements are addressed by the USC Foundation for Cross-Connection Control and Hydraulic Research Manual of Cross-Connection Control and by individual state plumbing codes. ASSE standards strictly govern product performance at the point of manufacture and certification.

Professionals navigating the broader landscape of backflow prevention service providers can reference the backflow prevention listings for qualified installers and testers operating under these standards.

How it works

Each ASSE standard defines a test protocol that a device must pass before it can be listed as compliant. The protocol maps to the hydraulic hazard the device is designed to address — specifically the two mechanisms that drive backflow events: backsiphonage (negative pressure in the supply line drawing contaminants backward) and backpressure (downstream pressure exceeding supply pressure and forcing contaminants upstream).

The standards also encode hazard classification, distinguishing between:

• High-hazard connections — where the substance that could enter the potable supply poses an immediate health risk (toxic chemicals, sewage, biological contaminants)
• Low-hazard connections — where the contaminating substance creates an aesthetic or operational problem but not an acute health threat

ASSE product standards are organized by device type. The core standards governing the most widely installed assemblies are:

The Reduced Pressure Principle assembly (ASSE 1013) is the most protective device in the series. It incorporates two independently acting check valves separated by a reduced-pressure zone maintained below supply pressure. If either check valve fails, the differential relief valve opens and discharges water to atmosphere rather than allowing backflow. This discharge is a deliberate design feature, not a malfunction.

The Double Check Valve Assembly (ASSE 1015) provides two independent check valves but no differential relief zone. It is appropriate only for low-hazard connections because a failure of both checks does not produce an atmospheric break — contaminants can reach the potable supply.

Pressure Vacuum Breakers (ASSE 1020) and Spill-Resistant Vacuum Breakers (ASSE 1056) protect only against backsiphonage and cannot be installed in configurations where backpressure is possible. Both require installation at a minimum height above the highest downstream outlet, as specified in the applicable plumbing code — typically 12 inches.

For context on how these device categories relate to cross-connection control program administration, the backflow directory purpose and scope describes how utilities structure their approved device lists.

Common scenarios

Irrigation systems — Outdoor irrigation connected to a potable supply represents one of the highest-volume applications for ASSE-listed devices. Where backpressure is possible (pressurized booster pumps), ASSE 1013 is required in most jurisdictions. Where only backsiphonage is the risk, ASSE 1020 or 1056 is frequently accepted, subject to elevation requirements.

Fire suppression systems — Fire sprinkler connections require detector assemblies capable of identifying unauthorized draws on the fire line. ASSE 1047 (for high-hazard chemical additives in the fire system) and ASSE 1048 (for non-additive systems) are the applicable standards. NFPA 13 cross-references these ASSE designations directly.

Commercial and industrial process connections — Facilities using chemical injection, boiler feed water, or cooling towers present high-hazard cross-connection scenarios. ASSE 1013 is the standard minimum for these applications under the IPC and UPC.

Healthcare facilities — Medical gas and equipment supply lines, dialysis systems, and laboratory connections are governed by both ASSE backflow standards and facility-specific requirements under the American Society for Healthcare Engineering (ASHE) guidelines and applicable state health codes.

Residential service connections — Many municipal cross-connection control programs require an ASSE 1015 or 1013 assembly at the meter where the property use triggers a hazard assessment — multi-unit housing, in-ground irrigation, or home-based businesses with chemical use.

Decision boundaries

Selecting the correct ASSE standard is a function of three variables: the hazard level of the cross-connection, the backflow mechanism possible at the connection, and the installation conditions (orientation, elevation, drainage availability).

Hazard level governs whether a high-hazard assembly (ASSE 1013, 1020, 1047, 1056) or a low-hazard assembly (ASSE 1015, 1048) is permissible. A water utility or local authority having jurisdiction (AHJ) makes the hazard classification based on the use at the point of connection. This classification is not interchangeable — a facility classified as high-hazard cannot substitute an ASSE 1015 assembly where ASSE 1013 is required, regardless of device availability or cost.

Backflow mechanism determines whether the device selected covers the full range of risk. PVBs (ASSE 1020, 1056) are categorically prohibited where backpressure conditions exist. A pressurized downstream system — such as a boiler or a pumped irrigation loop — eliminates PVBs from consideration even if the hazard level would otherwise allow them.

Installation conditions affect whether a device that passed ASSE certification testing will perform as tested in the field. ASSE 1013 assemblies require a downstream drainage path for relief valve discharge; installations lacking floor drains or proper containment cannot support an RP assembly regardless of hazard classification. ASSE 1020 assemblies require installation above the highest outlet and must remain accessible for annual testing, which is mandated under cross-connection control programs in most states.

Testing and inspection obligations are distinct from the ASSE product standard itself. ASSE publishes a separate series — the 5000-series — covering competency requirements for backflow prevention assembly testers. Most state licensing boards and water utilities reference ASSE 5000-series criteria when defining tester qualification standards, though state-specific requirements govern whether ASSE certification alone satisfies licensure. The how to use this backflow resource page describes how service professionals and water authority personnel are organized within this reference system.

References

• ASSE International — Product Standards
• American National Standards Institute (ANSI)
• IAPMO — Uniform Plumbing Code (UPC)
• International Code Council — International Plumbing Code (IPC)
• [NFPA 13 — Standard for the Installation of Sprinkler Systems](https://www.nfpa.org/codes-and-standards/all-codes