- The exam is 50 multiple-choice questions in two hours, closed book, with a 70% passing score.
- Initial cost is $100 exam plus $300 certification, $400 total; retake is $100 and renewal is $300.
- Five published competencies cover principles, equipment, safety, regulated substances, and water damage. ACAC publishes no percentage weights.
- Study the full required references, not just the highlighted S500 sections; the study guide is only a starting map.
Which CRMR This Sheet Covers
Several credentials in different industries share the acronym "CRMR." This page covers exactly one: Council-certified Residential Microbial Remediator, issued by the American Council for Accredited Certification (ACAC). Keep the letters straight on your application and your résumé: the credential is abbreviated CRMR, not CMR or CMRS. Those are separate ACAC designations with their own handbooks, and nothing on this sheet borrows their objectives.
If you are still orienting yourself, the explainers on what CRMR certification is and what CRMR stands for cover the basics. This page assumes you are past that and want the facts in one place.
Exam Format at a Glance
| Item | CRMR Fact |
|---|---|
| Certifying body | American Council for Accredited Certification (ACAC) |
| Questions | 50 multiple choice |
| Answer choices | At least four per question |
| Time limit | Two hours (the written exam duration, not a course length) |
| Materials | Closed book |
| Passing score | 70% |
| Question order | Questions and answers are randomized |
| Results | Electronic, available immediately, confirmed by email |
| Testing provider | Kryterion, Inc. (authorized testing centers or secure online video proctoring) |
| Alternative | Instructor-proctored vocational option, by arrangement |
One trap: ACAC's general examinations page mentions a range of 75 to 120 questions. That range does not describe this credential. Use the CRMR-specific handbook figure of 50 questions. For a deeper look at the arithmetic of 70% on 50 questions, see the CRMR passing score breakdown.
What the format implies for your prep
- Closed book means recall, not lookup. You cannot search the S500 or the AIHA text mid-exam, so definitions and decision rules need to be in your head.
- Randomization defeats memorized sequences. Learning "answer C" patterns from any source is useless; understanding why an option is right is not.
- Two hours for 50 items is roomy. Pacing is rarely the problem; careless reading of scenario wording is.
Fees and Money Facts
| Cost Item | Amount (USD) |
|---|---|
| Examination fee | $100 |
| Certification fee | $300 |
| Initial total | $400 |
| Retake | $100 |
| Renewal (every two years) | $300 |
These figures are ACAC's, not a prep provider's. Optional training, reference books, and practice materials cost extra and vary by seller. No preparatory course is mandatory for the CRMR. For a full budgeting walkthrough, read the CRMR certification cost breakdown.
Eligibility and the Application Window
The process, in order:
- Attest that you are currently employed in microbial remediation.
- Submit the application and complete identity verification.
- Pass the examination.
- Receive certification-board approval.
Notably absent: ACAC specifies no minimum years of experience, no project sheets, and no mandatory training course for the CRMR. The current-employment attestation is the gate, which is why people entering the field without a job in remediation should read the CRMR requirements guide before spending money.
The deadline wording problem
The current online application gives six months to complete the process, while the handbook still carries older 90-day and notarized-paper language. Do not assume either is correct in isolation. Follow the current application instructions and confirm the operative authorization deadline with ACAC before you schedule. For scheduling logistics, see CRMR exam dates and testing windows.
Course completion is not certification
This is a vocational designation and is not CESB-accredited. Finishing a training course, or passing an exam taken solely to satisfy a state license, does not by itself confer ACAC certification. The board approval step is what makes the credential yours.
The Five Competency Areas
ACAC publishes five exam-related competency statements. They are unweighted: no official percentage split has been verified, so treat all five as fair game rather than guessing at proportions. The complete CRMR domains guide goes deeper on each.
Domain 1: Basic Principles of Microbial Remediation
Understand the principles as described in the listed reference texts. This is the broadest area, anchored to the AIHA mold text and the IICRC standards.
- Be able to explain the reasoning behind containment, source removal, and cleaning, not just recite steps.
- Know the vocabulary the references use; glossary fluency pays off on closed-book recall.
- Expect questions that test whether you apply a principle to a described situation.
Domain 2: Equipment, Supplies, Calibration and Operation
Maintain familiarity with the equipment and supplies needed for a project, plus the methods for calibrating and operating that equipment.
- Know what each tool is for and when it is the wrong tool.
- Calibration is named explicitly in the competency, so do not skip it as "manufacturer trivia."
- Pair equipment knowledge with the limits of what its readings can tell you.
Domain 3: Safety Hazards and Protection
Appreciate the safety hazards of microbial remediation projects and follow procedures that protect both building occupants and remediation workers.
- The competency specifically includes regulatory awareness, safe work practices, and appropriate PPE.
- Think two audiences: the people living or working in the building, and your own crew.
- Match protective measures to the hazard described, rather than defaulting to "maximum everything."
Domain 4: Regulated Substances
Recognize that remediation may bring you into contact with regulated substances such as lead and asbestos.
- The operative verb is "recognize." The competency is about spotting when a job crosses into regulated territory.
- Know that suspect materials change what you may do next, and who may need to be involved.
- Do not stretch this into a claim that CRMR holders are licensed to abate these materials; the competency is recognition and awareness.
Domain 5: Water Damage in the Indoor Environment
Properly address water damage in the indoor environment.
- Moisture is the root cause of most microbial problems, so water-damage logic ties back to Domain 1.
- This is where the IICRC S500 water-damage standard does the heavy lifting.
- Expect cause-and-response thinking: what the water source and conditions imply for what you do.
Required References and Edition Traps
ACAC's required references are the real syllabus. The study guide groups preparation under three reference headings, which are preparation categories rather than extra official exam domains:
- AIHA: Recognition, Evaluation & Control of Indoor Mold, second edition (2020)
- IICRC S500: ANSI/IICRC S500-2021, fifth edition
- IICRC S520: S520-2015 with R520-2015 (third editions), or S520-2024 (fourth edition)
The ACAC Code of Conduct is also a required reference. Candidates routinely forget it because it is not a technical manual, yet it is on the list.
Choosing your S520 edition
Because ACAC lists both the 2015 pair and the 2024 edition, confirm with ACAC which edition your testing window expects, and study that one consistently rather than mixing them. These reference editions do not establish a numbered "2026 exam version"; there is no such label in the public materials.
Scenario Prompts to Rehearse
The five competencies read like job tasks, so rehearse them as job situations. These are study prompts, not actual exam questions, and nothing here reproduces exam content:
- Containment decision: A homeowner describes visible growth after a slow leak. What do the references say about assessing the moisture source before you touch the material?
- Equipment sanity check: A moisture or air-sampling reading looks off. What would you verify about calibration and operation before trusting it?
- Two-audience safety: Occupants remain in adjacent rooms during work. Which protections serve them, and which serve your crew?
- Suspect material: Demolition would disturb old finishes or insulation of unknown composition. What does "recognizing regulated substances" require of you before proceeding?
- Water first: Standing water and wet materials are present alongside mold. How does the S500 framework shape the order of operations?
Work each prompt out loud from memory, then check yourself against the references. If you want structured practice in this style, the CRMR practice test is built around scenario-based questions, and the CRMR study guide shows how to fold them into a plan.
Sequencing Your Review
You do not need a generic study system; you need an order that follows how the competencies depend on each other. Water and principles underpin everything else, so they go first.
Principles and Water (Domains 1 and 5)
- Read the AIHA text's core sections and the S500 highlighted sections together.
- Build a glossary sheet from S500 pages 99-118.
Equipment and Calibration (Domain 2)
- List each tool, its purpose, its limits, and its calibration logic.
Safety and Regulated Substances (Domains 3 and 4)
- Study PPE selection, safe work practices, and regulatory awareness.
- Practice recognizing when a job exceeds ordinary remediation.
Integration and Code of Conduct
- Run mixed scenario sets; read the ACAC Code of Conduct and the S520 material.
Stretch or compress this depending on your field exposure. Someone who handles water-damage jobs daily can shorten Week 1; someone who has never touched calibration should lengthen Week 2.
Renewal Cheat Block
- Term: two years
- Credits required: 40 total
- Breakdown: 10 for continued field activity plus 30 hours of professional development
- Cost: $300
- Housekeeping: retain evidence for audit and submit the required current photo
Start logging professional development the day you are certified; reconstructing 30 hours from memory at the two-year mark is miserable. ACAC's recertification procedures page is the authority for current rules.
Pass Rate, Salary and Jobs: Context
Pass rate
An earlier review attributed 37 passes from 37 exam administrations (100%) in 2025 to ACAC's 2025 Exam Pass Ratio report. That statistic was not independently re-verified here, because the PDF could not be re-fetched. The report reportedly includes retakes and exams taken solely for state licensing, and 37 administrations is a very small sample. Do not read it as a first-attempt probability or a promise about your own result. The CRMR pass rate analysis treats it with the caution it needs, and how hard the CRMR exam is addresses difficulty on its own terms.
Salary and value
Occupation-level earnings for remediation work are one thing; a pay premium caused specifically by holding the CRMR is another, and the second has not been demonstrated. Treat any single salary figure with suspicion. The CRMR salary guide and the worth-it ROI analysis separate those two questions. For the hiring side, see CRMR jobs.
Prep provider landscape
Comparators include Indoor Sciences, Zack Academy, IAQ Training Institute, IAQschool.online, and CleanHealth Environmental. This is a list, not a ranking or endorsement, and some pages could not be re-checked. Because provider copy can conflict with issuer instructions, take certification facts from ACAC and use providers only for the training itself. See CRMR training for how to evaluate options.
Key Takeaway
The cheapest way to waste money on this credential is to confuse a course with certification, or a vendor's page with ACAC's. Verify fees, deadlines, and edition requirements with ACAC, then spend your study time on the full references, not a summary of them.
FAQ
The CRMR exam has 50 multiple-choice questions with at least four answer choices each, and the passing score is 70%. It runs two hours and is closed book. Ignore the 75-120 question range on ACAC's general examinations page; it does not describe this credential.
The initial cost is $400: a $100 examination fee plus a $300 certification fee. A retake is $100, and renewal every two years is $300. Training and study materials are optional and priced separately by their sellers.
ACAC specifies no minimum duration of experience, project sheets, or mandatory preparatory course for the CRMR. You do need to attest to current employment in microbial remediation, verify your identity, pass the exam, and receive certification-board approval.
No. They are separate ACAC credentials with their own handbooks. This cheat sheet covers only the CRMR, and no CMR or CMRS objectives are included. Use the CRMR-specific handbook when preparing.
Certification lasts two years. Renewal requires 40 recertification credits (10 for continued field activity plus 30 hours of professional development), a $300 fee, a current photo, and retained evidence in case of audit. Confirm current procedures on ACAC's recertification page.