1.1 About ASSE 5110 and the Series 5000 Program

1.1 About ASSE 5110 and the Series 5000 Program

Quick Answer: ASSE 5110 is the national Backflow Prevention Assembly Tester certification under the ASSE/IAPMO/ANSI Series 5000 standard. Certified testers field-test RP (ASSE 1013), DC (ASSE 1015), PVB (ASSE 1020), and SVB (ASSE 1056) assemblies so potable water stays safe. The credential is a third-party certification independent of trainers, is held by 19,000+ professionals, and is accepted by many jurisdictions (including California SWRCB recognition). Official program home: asse-plumbing.org.

Why this chapter matters

Every other chapter in this guide—hydraulics, assembly internals, field-test steps, gauge discipline, codes—exists because a tester’s annual report is how water purveyors and authorities having jurisdiction (AHJs) decide whether a customer’s backflow assembly is still protecting the public supply. If you do not understand who issues the credential, what the credential authorizes, and why jurisdictions trust it, you will treat the written and practical exams as memorization chores instead of public-health gatekeeping. The exam measures whether you can be trusted with that gate.

Who is ASSE International?

ASSE International is a chapter of IAPMO (International Association of Plumbing and Mechanical Officials). ASSE develops and maintains both product performance standards (for example, the device standards that define how an RP or PVB must perform) and professional qualification standards (the Series 5000 family that defines who is qualified to test, repair, survey, or administer backflow programs).

That dual role matters on the exam and in the field:

A product listing tells you the hardware met a performance standard when manufactured. A 5110 certification tells the purveyor that you demonstrated the knowledge and hands-on skill to field-test that hardware correctly. Do not confuse the two number families: 10xx numbers name devices; 51xx numbers name people credentials.

Series 5000: the Cross-Connection Control Professional Qualifications Standard

The ASSE/IAPMO/ANSI Series 5000 is the consensus professional qualifications standard for cross-connection control. It is the legal and technical backbone of the ASSE backflow certification program. When a jurisdiction says it “accepts ASSE 5110,” it is accepting a credential whose training, written exam, and practical exam were designed against Series 5000 competencies—not against one school’s house syllabus.

Series 5000 currently frames five related credentials:

For this guide, 5110 is the focus. The other credentials are a career path, not deep exam content in Chapter 1. Know that they exist, know that they share the Series 5000 umbrella, and know that holding 5110 does not automatically authorize you to repair, survey, or administer—each credential has its own scope and exam.

What a 5110 tester actually does

A Backflow Prevention Assembly Tester performs the periodic field test (commonly annual, subject to purveyor and code rules) on installed testable assemblies. In practice that means you:

1. Identify the assembly type and confirm it is appropriate for the hazard and installation (orientation, elevation, clearances, drainage for RP relief discharge, and so on).
2. Hook up a calibrated differential pressure gauge (3-valve or 5-valve kit) with correct high/low hose discipline.
3. Execute an ASSE-recognized field-test procedure—commonly USC Manual of Cross-Connection Control, 10th Edition, and also including ASSE, EPA, and other recognized methods taught by your school.
4. Record opening points, check tightness, and relief/air-inlet behavior against pass criteria.
5. Report results to the water purveyor or AHJ on the required form, including fail-mode findings when an assembly does not meet criteria.

The four assemblies on the practical exam—and the core of day-to-day tester work—are:

You will also study detector assemblies (RPDA 1047, DCDA 1048) and non-testable devices for recognition, but the practical exam gate is the four assemblies above.

Why public health depends on accurate annual tests

Potable distribution systems are pressurized networks full of cross-connections—places where non-potable fluids can reverse into drinking water under backpressure or backsiphonage. Testable assemblies are mechanical safety devices with springs, seals, and moving parts that foul, stick, or wear. An assembly that passed last year can fail this year after sediment, thermal shock, freezing, vandalism, or simple age.

The tester is the last skilled person who:

• Measures whether the hydraulic differentials that make protection work still exist
• Catches a fouled check or a relief valve that no longer opens at the required point
• Forces repair or replacement before a reverse-flow event contaminates a building, a neighborhood main, or a community supply

False “pass” reports are not paperwork errors—they are public-health failures. That is why ASSE requires both a closed-book written exam and a no-notes practical under a proctor. The program is designed so that a credential on a badge means a demonstrated skill, not attendance alone.

National third-party certification (independent of trainers)

ASSE emphasizes that 5110 is a nationally recognized third-party certification independent of all training course providers and instructors. In plain language:

• Your instructor teaches the 40-hour course.
• A separate exam facilitator (not the instructor) administers the written exam.
• An ASSE-approved proctor witnesses the practical.
• ASSE (not the school) owns the exam content, maintains certification records, and publishes the Certified Professionals list.

That separation is intentional. Jurisdictions and employers can trust the credential because the school cannot write the test to its own shortcuts, and the instructor cannot grade the people they just taught. When you see “ASSE certified” on a purveyor’s approved-tester list, that independence is part of what the purveyor is buying.

ASSE maintains certification records, notifies individuals and schools when recertification is due, and publishes searchable directories of certified professionals and approved schools at asse-plumbing.org (and related IAPMO/ASSE portals).

Scale and jurisdiction acceptance

ASSE reports more than 19,000 certified backflow professionals across all 50 states and parts of Canada, with 100+ ASSE-approved schools. That scale means:

• Your credential can travel when you move or bid work in another state (subject to local AHJ acceptance—always verify).
• Employers and purveyors can verify you on a national list rather than relying on an untraceable local card.
• The exam content is aligned to a national standard, even when local codes add state-specific rules.

California example: In a June 17, 2025 letter, the California State Water Resources Control Board (SWRCB), Division of Drinking Water, recognized the ASSE 5110 program as meeting requirements in Section 3.4.1 of the state’s Cross-Connection Control Policy Handbook. That recognition is time-bounded under California’s handbook transition rules—always confirm the current acceptance window with SWRCB or your local agency—but it is a concrete illustration that major jurisdictions treat ASSE 5110 as a defensible tester credential.

Other states and cities may accept ASSE alone, accept ASSE alongside AWWA/ABPA/local programs, or require dual registration. The Series 5000 credential is the portable core; the local permit or tester number is the jurisdiction-specific wrapper.

How this guide uses 5110 scope

Throughout later chapters you will see device numbers, USC 10th criteria, gauge procedures, and installation rules. Keep three identity rules straight from day one:

1. 5110 authorizes testing and reporting, not unrestricted repair or program administration.
2. Series 5000 is the professional standard; 1013/1015/1020/1056 are product standards for the assemblies you test.
3. Official program information lives at asse-plumbing.org under personnel certification / backflow prevention—use it when your employer or AHJ asks for the source of a requirement.

If you can explain those three rules in one minute to a building owner, you already understand more about the credential’s purpose than many first-week students.

Realistic scenario

You finish a 40-hour course in another state and apply to be listed with a California water district. The district’s checklist asks: (1) proof of current ASSE 5110, (2) gauge calibration sticker within 12 months, (3) local tester registration if required. You produce your ASSE certificate and online Certified Professionals listing. Because SWRCB has recognized ASSE 5110 under the CCCPH tester rules for the applicable period, the district can accept the credential without inventing a new exam—while still requiring its own forms, fees, and annual report process. That is how national third-party certification and local control work together.