- What You Are Actually Preparing For
- Eligibility and Application: Do This Before You Study
- Exam Format, Delivery, and Scoring
- The Nine-Domain Study Map
- Reference Map: EPA, Drying Text, and Ethics
- Thinking Like an Investigator: Instruments and Corroboration
- A Domain-Sequenced Study Schedule
- Exam Day Logistics
- Cost, Renewal, and Career Value
- Frequently Asked Questions
- The exam has 100 multiple-choice questions in three hours, closed book, with a 75% passing criterion set by modified Angoff.
- Eligibility is documented before you test: four project sheets, transcripts where applicable, verifications, and unanimous certification-board review.
- ACAC publishes nine official domains but no percentage weights, so study all nine rather than guessing at emphasis.
- Read the EPA moisture guidance, the drying text, and the ACAC Code of Conduct in full, not just highlighted pages.
What You Are Actually Preparing For
CMCI here means the Council-certified Moisture Control Investigator credential, administered by the American Council for Accredited Certification (ACAC). Certification decisions are made by ACAC's CMCI Certification Board, and testing is delivered through Kryterion, Inc. Several unrelated credentials share the same four letters, including a construction-management certificate from a different organization, so make sure every resource you buy is written for the ACAC moisture credential. If you need a refresher on terminology first, see What Is CMCI Certification? and What Does CMCI Stand For?.
The credential tests whether you can investigate moisture problems in buildings: where water comes from, how it moves through assemblies, how to measure it, how to dry it, and how to document and report it ethically. That is investigative reasoning, not memorization of a product catalog. This guide builds your preparation around that fact. For a one-page recap of the facts below, the CMCI cheat sheet is a useful companion.
Eligibility and Application: Do This Before You Study
Many candidates treat the application as paperwork to finish after studying. With this credential, the application is a gate with real lead time, so start it early. The full walkthrough is in CMCI Requirements: Eligibility, Prerequisites & How to Qualify; the essentials are below.
Two Qualifying Routes
| Route | Education | Experience |
|---|---|---|
| Experience-based | High-school diploma or GED | Two years of documented relevant moisture-control field experience |
| Education-based | A qualifying two-year postsecondary degree, or equivalent 15 qualifying science-related credits | At least one year of relevant experience |
Relevant education fields include engineering, science, architecture, industrial hygiene, and related sciences. If you use the education route, gather your transcripts early, since obtaining official copies can take time.
What You Submit
- Four project sheets describing your relevant moisture-control investigation work
- Applicable education transcripts
- Application verifications, including an electronic affidavit and required email verifications
- Examination and then unanimous certification-board review
Write your four project sheets so they show investigation, not just remediation labor: what you observed, which instruments you used, what you concluded, and what you recommended. That framing matches how the exam thinks.
Exam Format, Delivery, and Scoring
- Questions: 100 multiple choice, at least four answer choices each
- Time: three hours
- Book policy: closed book
- Passing criterion: 75%, set by the certification board using the modified Angoff method
- Delivery: testing center or online video-proctored
- Presentation: randomized question and answer order, with immediate results
Three hours for 100 questions gives you roughly 1.8 minutes per question, which is comfortable for recall items but tight for scenario items that ask you to interpret observations. Practice reading a scenario, naming the likely moisture mechanism, and eliminating answers that skip a verification step.
For the scoring details, see CMCI Passing Score: Exactly What You Need to Pass. For difficulty context, How Hard Is the CMCI Exam? explains how to judge your own readiness.
The Nine-Domain Study Map
ACAC's scope document, CMCC and CMCI Examinations (approved March 6, 2024), lists nine domains that expressly cover CMCI. The chart is unweighted, and no domain question allocations are published, so you cannot responsibly skip any area. The candidate handbook groups its content under eight headings (seven technical plus the ACAC Code of Conduct) and does not separately label Plumbing or Project documentation. Treat the nine-domain chart as your working map, and treat ethics as required knowledge that runs through all of them. Our complete guide to all 9 CMCI content areas goes deeper on each one.
Domain 1: The Science of Water
The foundation for every other domain. Expect to reason about how water exists and moves in building environments.
- Phases of water and how vapor, liquid, and bound moisture behave in materials
- Relative humidity, temperature, and condensation relationships
- Driving forces for moisture movement and how materials absorb and release moisture
Domain 2: Site Drainage
Water that never reaches the building cannot damage it, so investigators start outside.
- Grading, surface water management, and runoff paths toward foundations
- Gutters, downspouts, and discharge locations
- Linking exterior water patterns to interior symptoms
Domain 3: Foundations
Below-grade conditions are a frequent source of chronic moisture complaints.
- Foundation types and typical moisture pathways
- Groundwater, hydrostatic pressure, and capillary movement
- Crawlspace and basement conditions and what they imply for the rest of the structure
Domain 4: Walls, ceilings, and floors
Interior assemblies where hidden moisture is hardest to confirm.
- Assembly layers, vapor movement, and where moisture accumulates
- Reading stains, deformation, and surface changes as clues rather than conclusions
- Choosing which instrument and which corroborating observation comes next
Domain 5: Roofs and building envelope assemblies
The envelope is the primary water-management layer of the building.
- Roof assemblies, penetrations, flashing, and drainage
- Envelope continuity and common intrusion points
- Distinguishing bulk water entry from condensation and air leakage
Domain 6: Plumbing
Supply and drain failures produce distinct moisture signatures.
- Supply-line, drain, fixture, and appliance leaks and their patterns
- Separating plumbing sources from envelope or condensation sources
- Documenting the evidence that points to a plumbing origin
Domain 7: HVAC
Mechanical systems both cause and cure moisture problems.
- Condensation, condensate drainage, and duct-related moisture
- Ventilation and humidity control in the building
- How HVAC operation affects readings and drying conditions
Domain 8: Structural Drying
The most procedure-heavy domain, anchored to the prescribed drying text.
- Drying principles, equipment roles, and monitoring progress
- Moisture-meter and infrared interpretation, and where each fails
- Knowing when drying goals are met versus when more investigation is needed
Domain 9: Project documentation
Findings that are not documented defensibly are not findings.
- Recording observations, readings, locations, and conditions consistently
- Separating observation from interpretation in reports
- Ethical reporting duties under the ACAC Code of Conduct
Reference Map: EPA, Drying Text, and Ethics
ACAC identifies three required references. Map each to the domains it serves, and read them in full. The handbook's selected review pages supplement the prescribed references; they do not establish exhaustive exam coverage, and the same caution applies to any third-party summary.
| Reference | Primary domains served | How to use it |
|---|---|---|
| EPA, Moisture Control Guidance for Building Design, Construction and Maintenance (December 2013) | 1, 2, 3, 4, 5, 7 | Public document. Read it end to end, then tie each section to a domain. |
| Ken Larsen et al., Leadership in Restorative Drying, fourth edition (2014) | 1, 8, 9 | Core text for drying principles and monitoring. Confirm you obtain the edition the handbook names. |
| ACAC Code of Conduct | All, especially 9 | Study it as scenario material: what is the correct professional action? |
A note on editions: ACAC's linked public vendor page describes the book as a 2014 Gold Edition, while the handbook uses the fourth-edition label. Do not assume they are identical. Ask ACAC which printing to use before you spend money.
Thinking Like an Investigator: Instruments and Corroboration
The exam rewards a disciplined chain of reasoning: observation, measurement, corroboration, conclusion, next step. Scenario questions commonly present a symptom and ask what to do or conclude. The strongest answer usually avoids jumping to a conclusion from a single data point.
A Practical Reasoning Pattern
- Observe: What is visible, and where? What is the building's history?
- Hypothesize: Which source or mechanism could produce this pattern (site drainage, foundation, envelope, plumbing, HVAC, condensation)?
- Measure: Which instrument fits, and what are its limits in this material?
- Corroborate: What second observation would confirm or rule out the hypothesis?
- Decide the next step: More investigation, drying, repair recommendation, or documentation?
Practice running every sample question through those five steps. Our CMCI practice tests are built around scenarios of this type, with explanations that tie each answer back to the reasoning rather than just naming a letter.
A Domain-Sequenced Study Schedule
Generic study advice matters less than ordering. Water science underpins everything, so it comes first; documentation and ethics come last because they synthesize everything else. Adjust the length to your experience, and spend extra time on domains where your field work has been thin. If you spend most of your time on interior drying jobs, for example, give site drainage and foundations more time than you think they need.
Science of Water and the EPA guidance
- Read the EPA guidance in full while studying Domain 1
- Build a one-page sketch of how moisture moves and condenses
Exterior and below-grade: Domains 2 and 3
- Trace water from roof to site to foundation
- Write practice scenarios linking exterior conditions to interior symptoms
Assemblies and envelope: Domains 4 and 5
- Focus on where moisture accumulates in layered assemblies
- Drill the instrument-limitations reasoning pattern
Plumbing and HVAC: Domains 6 and 7
- Practice separating plumbing, condensation, and envelope sources
Structural Drying and Project documentation: Domains 8 and 9
- Work through the drying text alongside the Code of Conduct
- Take timed full-length practice exams and review every miss
Key Takeaway
Use practice results to decide where to spend final-week time. If you consistently miss scenario questions that blend two domains (say, HVAC and condensation in walls), review the blend, not just each domain alone. See the CMCI study guide hub for related resources.
Be Selective About Third-Party Materials
Some publicly visible preparation listings use the CMCI label but preview generic quality-control or process-control questions that have little to do with moisture investigation, and a label or partial preview does not establish complete or accurate coverage. Check any question bank against the nine ACAC domains and the required references before you rely on it. Official ACAC resources, including the handbook and its free study guide, should anchor your preparation.
Exam Day Logistics
- Choose your delivery mode early. You can test at a testing center or online with video proctoring.
- For online delivery, you need your own computer, an approved webcam, a private location, and a continuous 2 Mbps upload/download connection. Test your setup in advance.
- Bring valid identification and follow the proctor's instructions exactly; verify current ID rules with ACAC and Kryterion.
- Remember the closed-book rule. Do not plan on references at your desk.
- Pace yourself. Answer confident items quickly and flag longer scenarios for a second pass within the three hours.
- Expect immediate results, and know the retake option (USD 100) in case it is needed.
Scheduling windows and deadlines are covered in CMCI Exam Dates: Testing Windows, Deadlines & Scheduling. Use ACAC and Kryterion as your source for policies, not rules from unrelated credentials.
Cost, Renewal, and Career Value
Fees
The initial US/Canada fee is USD 500, made up of USD 100 for the examination and USD 400 for certification covering the first two-year term. ACAC's current official application quotes USD 525 outside the US/Canada. A retake costs USD 100. A prep course is optional. See CMCI Certification Cost: Complete Pricing Breakdown for the full picture.
Keeping the Credential
Certification is valid for two years. Renewal costs USD 400 and requires 40 renewal credits (RCs): 10 for continued field activity plus 30 professional-development hours under current procedures. Retain your records for audit. Start logging activities from day one rather than reconstructing them later.
Career Value
Moisture investigators work in restoration, building consulting, inspection, and related fields, and the credential signals documented experience and board-reviewed competence. Be careful with salary claims. Earnings for moisture-investigation roles are not the same as construction-manager earnings, and broad occupational averages for inspection work are not CMCI-specific figures. No reliable CMCI-specific earnings number should be assumed. Our CMCI salary guide, CMCI jobs overview, and ROI analysis discuss how to evaluate the investment for your situation.
Frequently Asked Questions
The exam has 100 multiple-choice questions with at least four answer choices each, a three-hour limit, and a closed-book format. The passing criterion is 75%, set by the certification board using the modified Angoff method.
Yes. ACAC offers testing-center or online video-proctored delivery through Kryterion. Online candidates need their own computer, an approved webcam, a private location, and a continuous 2 Mbps upload/download connection.
No. ACAC publishes nine unweighted domains and no per-domain question allocations. Its 2025 Exam Pass Ratio document has no CMCI row, which should not be interpreted as a zero pass rate. Study all nine domains.
With a high-school diploma or GED, you need two years of documented relevant moisture-control field experience. With a qualifying two-year postsecondary degree or equivalent 15 qualifying science-related credits, you need at least one year. You also submit four project sheets and verifications.
Certification lasts two years. Renewal costs USD 400 and requires 40 renewal credits: 10 for continued field activity and 30 professional-development hours under current procedures. Keep records in case of audit.
Preparation for this credential is part paperwork, part science, and part professional judgment. Start the application early, study all nine domains against the required references, practice evidence-based reasoning, and confirm every procedural detail with ACAC. When you are ready to test your readiness, work through scenario-based questions on the CMCI Exam Prep practice site.