CIES Pass Rate 2026: What the Data Shows

The Short Answer: No Verified 2026 Pass Rate Exists

If you searched for the Council-certified Indoor Environmental Supervisor (CIES) pass rate hoping for a clean percentage, here is the honest answer: there isn't a verified current one. The American Council for Accredited Certification (ACAC), which issues the credential, has not published a numerical 2025 or 2026 pass rate that we could confirm. Any website quoting a precise figure for 2026 is either guessing, recycling a number from a different credential that shares the same acronym, or misreading an issuer report.

That may sound unsatisfying, but it is genuinely useful information. This article walks through exactly what ACAC does publish, where those documents contradict each other, why the numbers are too small to carry statistical weight, and what you should look at instead when judging whether you are ready. If you want the broader picture of difficulty, our guide on how hard the CIES exam is covers the qualitative side, and the companion page CIES Pass Rate 2026: What the Data Shows stays aligned with the same verified record.

What ACAC's Published Reports Actually Show

ACAC publishes annual documents that summarize certification activity and exam outcomes across its programs. For CIES, the picture is sparse:

Two points deserve emphasis. First, the 2025 data contains no usable pass rate at all. Second, the six current certifications recorded at the end of 2025 tell you something about the scale of this credential: it is a small, specialized population, not a mass-market exam with thousands of annual candidates.

The 2024 Conflict: 100% or 0%?

The most tempting numbers to quote are the 2024 ones, and they point in opposite directions. The 2024 Exam Pass Ratio report lists CIES with 2 exams taken, 2 passed, and a 100% rate. The 2024 Accredited Certification Activity report, covering the same year, lists 2 applicants, a 0% figure, and 7 current CIES certifications.

We do not substitute either figure for a current rate, and you should be skeptical of anyone who does. There are plausible reasons the two documents diverge. An "applicant" is not necessarily the same as someone who sat the exam in that calendar year, and the two reports may count different events, such as exam attempts versus certification decisions, or different time windows. But the issuer has not reconciled them publicly, so the responsible position is to present both and draw no conclusion from either.

Why a Tiny Candidate Pool Distorts Any Percentage

When the denominator is two, a percentage stops being informative. One more or one fewer passing candidate swings the result by 50 points. That is why a 100% in one report and a 0% in another can coexist without either telling you anything about how hard the exam is for a well-prepared candidate.

The practical lesson is that the pass rate is the wrong lens for this credential. A candidate deciding whether to invest in CIES should think about the requirements, the exam design, and the breadth of material, not about a ratio that cannot be estimated from available data. Our page on the CIES passing score explains the score threshold, which is a far more meaningful number than any attempt-based ratio.

What an Exam-Attempt Report Does and Does Not Measure

Even if ACAC published a clean percentage tomorrow, you would need to know what it counts. Exam-attempt reports of this kind include retakes and candidates who test solely for state licensing purposes. That means the figures do not establish first-attempt success. They also do not tell you how many people ever completed the full certification process, which requires a separate application, four project sheets, and verification of experience.

• Retakes inflate attempts. A candidate who fails once and passes on the retake appears as two attempts and one pass.
• Licensing-only candidates blur the picture. A person who takes the exam only to satisfy a state licensing rule is not pursuing CIES certification, and a licensing-only exam result does not itself confer CIES certification.
• Pass ratio is not demand. The figures say nothing about search volume or how many people are considering the credential.

Better Difficulty Signals Than a Pass Percentage

Rather than hunting for a ratio, evaluate the credential on the structural features that actually determine difficulty:

1. The cut score is high. The passing score is 75%, set using the Modified Angoff method, which relies on expert judgment about how a minimally competent supervisor would perform on each item.
2. The scope is wide. Five published competencies span asbestos, lead, hazardous materials, microbial contaminants and allergens, and chemicals.
3. The preparation list is long. The handbook points to a range of federal regulations and guidance documents, and warns that its study-guide pages are examples rather than exhaustive coverage.
4. Practical experience is a gate. You need documented field experience before you can even test, which means candidates arrive with real-world context.

For a deeper look at how these factors combine, see our article on how hard the CIES exam really is.

Exam Mechanics That Set the Bar

Understanding the format helps you judge your own readiness better than any aggregate statistic.

• Length and format: 120 multiple-choice questions, each with at least four answer options.
• Time: three hours, computer-delivered, closed book.
• Passing score: 75%, which on a 120-question test is a demanding threshold. The split between scored and unscored items is not published, so do not assume every question counts or that you can calculate an exact number of misses allowed.
• Delivery: proctored testing-center and online video delivery are both available. The handbook describes a fixed question set with randomized item and answer order. Adaptive testing is not described.
• Results: scores are available electronically immediately and confirmed by email.
• Practical component: no separate practical assessment is described.

For scheduling details and testing windows, see CIES exam dates and scheduling.

Five Competencies, Five Preparation Problems

The five competency headings published for CIES are unweighted. No public domain chart or percentages were verified, so we do not assign weights or name a "highest-weighted" area. What the handbook does say is that each competency addresses engineering controls, cleaning and removal methods, worker safety, and applicable regulations. That cross-cutting pattern is the key to studying: for every contaminant, expect to reason about how you would control it, remove it, protect workers from it, and comply with the governing rules.

For a full walkthrough of each competency, see the complete CIES exam domains guide, and for a distilled review sheet try the CIES cheat sheet.

The Hurdles Before You Ever Sit the Exam

The exam is only one stage. ACAC requires a qualifying combination of education and documented indoor environmental remediation experience:

• A related four-year degree or 30 qualifying college credits plus four years of documented experience; or
• A related two-year degree or 15 qualifying credits plus six years; or
• A high school diploma or GED plus eight years.

Experience must cover at least three of five areas: asbestos, lead, hazardous materials, microbial/allergens, and industrial hygiene, chemicals and toxicology. Applicants submit four project sheets, each describing the problem, the applicant's own responsibilities and actions, and the outcome, along with educational evidence where applicable and experience verification. ACAC expects actual field experience.

The application is submitted online with required email verifications, and approval requires a unanimous board vote. Timing is a known inconsistency in the issuer's own materials: the current application page describes a six-month window including the examination and a board that meets every four to six weeks, while the handbook gives 90 days and describes notarized forms and employer affidavits. We cannot resolve that conflict, so confirm the current rules with ACAC before you build a timeline. Full details are in our CIES requirements guide.

Cost is straightforward by comparison: $100 for the examination plus $400 for certification, including a $100 nonrefundable processing fee, for $500 total for the initial two-year term. A retake costs $100 and renewal costs $400. See the full CIES cost breakdown for context.

This pipeline is itself a reason the candidate pool is small and self-selected. Applicants have already shown years of field work before the exam, which is another reason a raw pass percentage would say little about the exam's difficulty for a newcomer.

Licensing-Only Test Takers Are a Different Population

One source of confusion in any attempt-based statistic is that some candidates take the exam for licensing rather than certification. Indexed content from the Florida Department of Business and Professional Regulation lists CIES among the examinations relevant to mold-remediation licensing, though a direct retrieval of that page was blocked, so treat that as an indexed-text observation rather than a fully verified legal statement. The state's accessible checklist for a mold remediator initial license by examination confirms that passing an approved examination is only one part of licensing; separate application, education and experience, fingerprinting, and insurance requirements also apply.

The takeaway: state licensing eligibility and ACAC certification eligibility are distinct. Passing for licensing does not make you a certified CIES, and exam-attempt counts can mix both groups together. If licensing is your goal, verify the current requirements directly with the state regulator.

A CIES-Specific Preparation Sequence

Because the competencies are unweighted, the sensible approach is to allocate time by your own weakest areas and by how much regulatory detail each demands. Here is one way to sequence an eight-week plan around the five competencies rather than around generic study habits:

For a fuller approach, see our CIES study guide, and when you are ready to test yourself under realistic conditions, use the CIES practice tests to drill each competency and track weak spots before exam day.

Frequently Asked Questions