Guide

ASSE 5110: the tester certification, explained

A complete guide to the ASSE 5110 Backflow Prevention Assembly Tester certification: every requirement, both exams, the 5000 series ladder, the three-year cycle, and how to verify an accredited school.

ASSE 5110 is the certification behind most of the backflow test tags hanging on assemblies across the country. It is the credential water authorities most commonly recognize when they ask whether a tester is qualified, and it is the anchor of a five-certification series covering the whole cross-connection control field. This guide lays out every requirement, what the exams involve, how the credential relates to the rest of the series, and how to make sure the school you pay is actually accredited to grant it.

Everything stated here about the certification's requirements comes from ASSE International's own published requirements. Where local rules enter the picture, and they always do in this trade, we say so explicitly.

What ASSE 5110 is

ASSE International is a standards body with a professional qualifications program for the trades that touch cross-connection control. The 5110 designation is its Backflow Prevention Assembly Tester certification: a credential that says its holder has documented trade experience, completed a minimum 40-hour course, passed a written exam, and demonstrated correct test procedure on real assemblies in front of an evaluator. Certification is granted for a three-year period, after which the holder recertifies.

The word assembly in the title is doing real work. Testable backflow preventers are assemblies: devices with shutoff valves and test cocks built in so a tester can isolate them and measure the performance of each internal component. The credential is about proving those components work, with a calibrated differential-pressure gauge and a prescribed procedure, not about eyeballing hardware.

Who this credential is for

The candidate pool is exactly who you would expect from the experience requirement: plumbers who want a recurring service line, irrigation contractors whose installed systems all carry testable devices, fire sprinkler technicians whose risers sit behind backflow protection, and municipal water workers whose employers run the compliance programs. It also fits facilities and maintenance staff at large sites with many assemblies, where an in-house tester saves the organization a contractor relationship. If your working life already involves water piping in any of these forms, the credential extends what you do rather than replacing it.

The requirements, all of them

Four requirements stand between a candidate and the certification:

• A minimum of five years of documented practical experience in installation or service of plumbing, mechanical, fire protection, lawn irrigation, or a related field
• A minimum 40-hour training course through an ASSE Accredited School
• A written exam of 100 questions, passed at 70 percent or higher
• A hands-on practical exam covering testing of assemblies under ASSE standards 1013, 1015, 1020, and 1056

There are no shortcuts around any of the four, and the sequencing is natural: document your experience, enroll in an accredited course, and take both exams through the school. Certification then runs on a three-year cycle.

The experience requirement in practice

Five years of documented practical experience is the gate. The field is defined broadly, installation or service in plumbing, mechanical, fire protection, lawn irrigation, or a related field, which reflects where backflow assemblies actually live. A journeyman plumber qualifies. So does an irrigation tech with five seasons of installs and service, a fire sprinkler fitter, and a municipal distribution operator. What matters is that the experience is real, practical, and documentable.

Documentation is the part people underestimate. Be ready to show employment history, license records, or employer verification covering the five years. If your background is a mix, say three years of irrigation and two of general plumbing service, present the whole picture; the requirement is five years across the recognized fields, not five years in a single title. If you are unsure whether your history qualifies, ask the accredited school before enrolling. They process these applications constantly and can tell you what will and will not pass review.

The 40-hour course

The minimum 40-hour course is where the trade knowledge you already have gets reorganized around one question: how do you prove an assembly protects the water? Expect classroom theory on hydraulics, backsiphonage and backpressure, degrees of hazard, and assembly construction, paired with substantial rig time running test procedures on real hardware.

A well-run course will take you through:

• Why backflow occurs: pressure relationships, backsiphonage, and backpressure in plain mechanical terms
• How each assembly family is built and how each internal component can fail
• The full field test procedure for each covered assembly family, repeated until it is second nature
• How to read, record, and interpret gauge results, including borderline and failing readings
• Reporting and documentation practices that water authorities actually accept

Two practical notes about the number. First, 40 hours is a minimum, and some schools run longer. Second, format varies by school: consecutive full days, split weekends, or blended self-paced theory with in-person lab. What cannot vary is accreditation. The course must come from an ASSE Accredited School for the certification to exist at the end of it.

The written exam

One hundred questions, 70 percent or higher to pass. The exam covers the course material: theory, procedures, hazard concepts, and assembly knowledge. Candidates with strong field backgrounds sometimes coast through the hands-on portions of the week and then get surprised by the theory questions, so give the classroom half of the course the same respect as the rig.

A useful self-check while studying: for each step of each test procedure, can you explain what the step proves and what a failed reading means about the hardware inside? If you can, the written exam becomes an exercise in reading carefully. If you can only recite step order, keep studying.

The practical exam and the four assembly standards

The practical exam is a hands-on demonstration in front of an evaluator, covering the testing of assemblies addressed by four ASSE product standards: 1013, 1015, 1020, and 1056. You do not need to memorize standard numbers to understand what this means. Together, those standards cover the main families of testable backflow preventers you will meet in the field.

In plain terms, the families are these. Reduced pressure principle assemblies, often called RP or RPZ in the field, use two check valves with a monitored relief zone between them and are the workhorses on high-hazard services. Double check valve assemblies use two checks in series without a relief zone and serve lower-hazard applications. Pressure vacuum breaker types use a check and an air inlet to protect against backsiphonage and are everywhere in irrigation, including a spill-resistant variation designed for locations where discharge from the standard type would be a problem.

Each family has its own test procedure, and the practical exam expects correct procedure on each: correct hose connections in the correct order, correct sequence of valve operations, correct reading and interpretation of the gauge, and correct restoration of the assembly to service. Evaluators watch process as much as outcomes. A plausible number reached by sloppy procedure is not a pass.

The way to arrive ready is rig repetition at the school. Ask up front how much individual hands-on time students get and how many assembly types are on the floor. A school with one crowded rig is a worse deal than a school with enough hardware for everyone to run every procedure multiple times, regardless of how the two compare on schedule or convenience.

The instrument behind the exam

The practical exam, and the career after it, runs on a backflow test kit: a differential-pressure gauge instrument in a 3-valve or 5-valve configuration with hoses and fittings. Schools provide kits for training and testing, and most candidates buy their own once certified. Either valve configuration can test the common assembly families; learn the one your school teaches, then learn the other, because you will encounter both in working life.

Where 5110 sits in the ASSE 5000 series

The tester credential is the entry point of a five-certification series that maps the whole cross-connection control field:

The 5120 Cross-Connection Control Surveyor credential is about identifying hazards: surveying facilities to find cross-connections and determine what protection each requires. The 5130 Backflow Prevention Assembly Repairer covers diagnosing and fixing assemblies that fail, which pairs naturally with testing in a shop that wants to keep failed devices in-house from red tag to retest. The 5140 Fire Sprinkler Cross-Connection Control Tester focuses on the fire protection side, where sprinkler system conditions and site rules differ from domestic water work. The 5150 Backflow Prevention Program Administrator is the management credential for the people who run compliance programs, often at utilities.

For most tradespeople the sensible sequence is 5110 first, since testing is where the recurring field demand is, then 5130 if your shop wants repair revenue, 5140 if fire work is your lane, and 5120 or 5150 if your career points toward surveys or program management. The series is a ladder, not a menu you must finish.

The three-year clock and recertification

Certification runs for a three-year period, and recertification runs through ASSE Accredited Schools, not through ASSE directly. Schedules and pricing come from the schools, which means availability and cost vary by provider and region. The recertification requirements themselves are fixed by certification level.

For the 5110 tester, that means recertifying is not a formality: there is a written exam and a hands-on practical every cycle. Treat the 8-hour class as a genuine refresher, particularly on any assembly family you test rarely in your day-to-day work, because the practical does not limit itself to whatever you happen to test most.

The scheduling rule worth tattooing on your calendar: you can recertify up to six months before your expiration date without losing any time on your certification. Early recertification does not shorten your cycle. That removes every excuse for brinkmanship. Book a seat early in your renewal window, because class schedules belong to the schools, seats are finite, and an expired certification can mean coming off water authority tester lists until it is put right.

Plan the recert class around your own busy season too. If irrigation startup is your heaviest stretch, a recertification seat booked into that window will either get skipped or cost you route days. The six-month early window exists precisely so you can slot the class into your slow period without penalty.

Verifying that a school is accredited

Because training and exams run through ASSE Accredited Schools, verifying accreditation is step zero of choosing a course. Do not settle for a course page that merely says certified or approved somewhere in the marketing copy. Confirm the school's ASSE accreditation directly, through ASSE's own listings or by asking the school for its accreditation credentials, and confirm it covers the specific certification you are pursuing.

A short due-diligence list before paying anyone:

• Confirm current ASSE accreditation for the 5110 course specifically, not just the school generally
• Confirm both the written and practical exams are administered as part of the program
• Ask how experience documentation is submitted and reviewed
• Ask about the retake policy for each exam, and get it in writing
• Confirm with your local water authority that certification from this school will be accepted where you work

The jurisdiction caveat, one more time

ASSE 5110 is widely recognized, but recognition is decided jurisdiction by jurisdiction. States and individual water authorities regulate backflow testing, and some operate their own programs or accept ABPA certification instead of or alongside ASSE. The same credential that makes you an approved tester in one service area may need to be supplemented by registration, reciprocity paperwork, or a different credential in the next one over.

The calls to make are to your state drinking water program and to the cross-connection control office at each water utility where you plan to work. Ask which certifications they accept, what registration they require, and how their approved tester list works. Ten minutes of phone calls protects a full week of training.

Is the credential worth the effort

The requirements are real: five documented years, a full training week, two exams, and a recurring three-year commitment. In exchange you get a portable, recognized credential in a compliance-driven trade where the work renews on a schedule. ASSE reports more than 19,000 ASSE-certified backflow professionals across all 50 states and parts of Canada, which tells you two things at once: the field is established enough to be recognized nearly everywhere, and small enough that a reliable tester still stands out in a local market.

If you have the five years, the path from here is short. Verify local acceptance, pick an accredited school, block out the course, and take both exams while the material is fresh. The three-year clock only starts once you pass.

Compare all five ASSE certifications

The instrument this trade runs on

Mid-West 845-5 5-Valve Test KitArbiter Mako MK5 Digital 5-Valve KitAcugauge TK Plus 3-Valve KitBAC-FLO-5 Test Kit

Confirm what your jurisdiction's test procedures require before choosing a kit.The kit guide.

Certification facts sourced from ASSE International's published requirements. The full 5000-series reference.