- The Short Answer: What a CMR Is
- Who Issues the Credential and How It Is Decided
- Why the Acronym Causes Confusion
- The Seven Exam Domains
- What the Exam Looks Like
- Who Qualifies to Apply
- The Application Walkthrough
- Fees and Optional Costs
- Reading the Pass Ratio Carefully
- Staying Certified: Renewal Credits
- Roles, Employers and Earnings Evidence
- A Domain-Ordered Starting Plan
- Frequently Asked Questions
- A CMR is a Council-certified Microbial Remediator, a credential issued by the American Council for Accredited Certification (ACAC).
- The exam has 100 multiple-choice questions, three hours, closed book, with a 75% passing criterion.
- Eligibility pairs documented remediation experience with education, and the application includes four project sheets.
- The initial US/Canada fee is USD 500; certification lasts two years, and renewal costs USD 400.
The Short Answer: What a CMR Is
On this site, a CMR is a Council-certified Microbial Remediator. It is a professional credential for people who plan, perform or supervise the remediation of microbial contamination, most often mold growth that follows water intrusion in buildings. Holding the designation signals that a candidate documented real field experience, satisfied an education requirement, and passed a closed-book examination built around remediation practice.
The credential is aimed at practitioners rather than casual students. Typical holders are remediation project managers, supervisors and lead technicians, along with people from industrial hygiene, engineering or building-science backgrounds who oversee remediation work. If you want the broader terminology picture, our explainers on what CMR stands for and what CMR certification is cover the naming from other angles.
Who Issues the Credential and How It Is Decided
The certifying organization is the American Council for Accredited Certification (ACAC). Certification decisions are made by its CMR Certification Board, which reviews each application and the candidate's examination result. Review is unanimous at the board level, which is one reason applications are not instant approvals: files are batched for board meetings rather than processed on demand.
Testing is delivered through Kryterion, Inc., the testing provider. Candidates can test at a testing center or take the exam online with video proctoring. That separation matters in practice: ACAC sets the standards and decides certification, while Kryterion handles scheduling mechanics, identity checks and exam delivery.
Why the Acronym Causes Confusion
"CMR" is shared by several unrelated credentials and professions, and search results mix them freely. Anything you read about exam fees, passing scores or domains for another credential called CMR does not apply to this one. Two lookalikes deserve a specific warning:
- CMRS: a related ACAC designation that shares an examination page and domain chart with the CMR. Eligibility and exam details are kept distinct, so do not assume CMR and CMRS requirements are interchangeable.
- NORMI's Certified Mold Remediator: a separately issued credential from a different organization. NORMI's own description confirms it is its own certification, and its syllabus does not define the ACAC exam.
Before paying for any course or practice material, confirm that it targets the ACAC Council-certified Microbial Remediator exam specifically. Some third-party question banks publish exam timing, passing scores, fees or renewal rules that conflict with ACAC's published information. When in doubt, the issuer's pages and the CMR Candidate Handbook govern. For an overview of how the pieces fit together, see our CMR certification overview.
The Seven Exam Domains
ACAC's examination objectives, approved February 21, 2024, list seven domains. ACAC publishes this chart without percentage weights, and the numbered subdomain columns on it are not weights either. Any resource claiming exact percentages per domain is describing its own materials, not the official exam blueprint. For a deeper walk through each area, read our complete guide to the seven CMR domains.
Domain 1: Principles & Equipment
The foundation: how microbial growth behaves and how remediation tools are selected and used.
- Moisture, growth conditions and containment concepts
- Air filtration, negative air and drying or cleaning equipment
- Matching equipment to the contamination scenario
Domain 2: Guidelines, Regulations & Standards
The published documents that define accepted practice, plus professional conduct.
- Edition-specific knowledge of the prescribed references
- ACAC Code of Conduct, which sits inside this domain rather than forming an eighth one
- Telling guidance apart from regulation
Domain 3: Water Damage
Water intrusion is the usual precursor to mold problems, so classification and response drive the rest of the job.
- Water source categories and damage classes
- Drying logic and timing
- What can be salvaged versus removed
Domain 4: Structural and Contents Remediation
The hands-on work of cleaning, removing and treating affected building materials and personal property.
- Choosing removal versus cleaning for different materials
- Work sequencing and containment integrity
- Handling and cleaning contents
Domain 5: HVAC System Remediation
Air-handling systems can distribute contamination, so they require their own approach.
- Assessing and isolating HVAC components
- Cleaning methods and when components are replaced
- Preventing cross-contamination during work
Domain 6: Project Documentation & Verification
Proving what was done and that it worked.
- Scope-of-work, logs and records
- Clearance and post-remediation verification concepts
- Communicating results to stakeholders
Domain 7: Safety
Protecting workers and occupants throughout the project.
- Respiratory protection selection and use
- Chemical safety, which sits within this domain
- Fall protection, also within this domain
Because the domains are unweighted, a sensible study approach is to treat none as skippable. Note, too, that the Code of Conduct, chemical safety and fall protection appear within existing domains and do not add to the seven.
What the Exam Looks Like
The exam consists of 100 multiple-choice questions, each with at least four answer choices, with three hours allowed. It is closed book. The passing criterion is 75%, set by the certification board using the modified Angoff method, a standard-setting approach in which subject-matter experts judge how a minimally competent candidate would perform on each item. Question and answer order are randomized, and results appear immediately after you finish. Our page on the CMR passing score goes deeper on what the 75% criterion means in practice.
| Feature | CMR Detail |
|---|---|
| Question count and type | 100 multiple-choice, at least four choices each |
| Time limit | Three hours |
| Materials | Closed book |
| Passing criterion | 75%, set by modified Angoff |
| Delivery | Testing center or online video-proctored |
| Scoring feedback | Immediate results |
Online Exam Logistics
Candidates testing remotely must supply their own computer, an approved webcam, a private location and a continuous 2 Mbps upload and download connection. Test your setup well before exam day; a marginal connection or shared room is a preventable reason to have a session disrupted. Candidates who prefer a controlled environment can use a testing center instead.
Prescribed References
The CMR Candidate Handbook names the texts the exam assumes you know comprehensively. They include:
- AIHA, Recognition, Evaluation & Control of Indoor Mold, second edition (2020)
- EPA, Mold Remediation in Schools and Commercial Buildings (2001)
- ANSI/IICRC S500-2021
- ANSI/IICRC S520-2015 with R520-2015, or S520-2024
- NIOSH, Respirator Selection Logic (2004)
For a structured approach to those texts, our CMR study guide maps reading to the seven domains.
Who Qualifies to Apply
There are two published routes to eligibility, and both combine education with field experience:
- Experience-heavy route: a high-school diploma or GED plus two years of documented microbial-remediation experience.
- Education-supported route: a qualifying two-year postsecondary degree or its equivalent of 15 qualifying science-related credits, plus at least one year of relevant experience.
Accepted education fields include microbiology, engineering, science, architecture, industrial hygiene and related sciences. A prep course is optional; it is not a prerequisite. Our CMR requirements breakdown explains how to document either route.
The Application Walkthrough
The submission package consists of four project sheets, applicable education transcripts, the online application, an electronic affidavit and required email verifications. The handbook additionally requests employer affidavits. After you submit, you sit the exam, and then the CMR Certification Board gives your file a unanimous review.
Where ACAC's Own Pages Disagree
Candidates should know that the issuer's materials contain some inconsistencies, and the sensible response is to confirm with ACAC before relying on any single page:
- The current application page allows six months and online/email verification, while the handbook says 90 days and retains notarized-paperwork and employer-affidavit instructions.
- The application page describes board meetings every four to six weeks; the handbook says approximately four weeks.
- The exact application uses Florida mold-assessor wording, while the handbook's licensing paragraph refers to CMI.
These discrepancies do not change what the remediation credential is, and they do not establish that the credential suits any particular state license. If you need the credential for licensing, check with the relevant licensing authority directly. For scheduling realities, see our exam dates and scheduling guide.
Key Takeaway
Start gathering project documentation and transcripts before you pay for anything else. The four project sheets and verification steps are the slowest part of the process, and the paperwork rules vary slightly between the handbook and application page.
Fees and Optional Costs
The initial fee for US and Canadian candidates is USD 500, made up of a USD 100 examination fee plus a USD 400 certification fee covering the first two-year term. ACAC's current official application quotes USD 525 outside the US/Canada. The certification fee includes a non-refundable USD 100 processing component. A retake costs USD 100, and renewal costs USD 400.
| Item | Amount |
|---|---|
| Initial total (US/Canada) | USD 500 (USD 100 exam + USD 400 certification) |
| Initial total outside US/Canada | USD 525 per current application |
| Retake | USD 100 |
| Renewal (two-year term) | USD 400 |
| Processing component | USD 100, non-refundable, included in certification fee |
Paid prep courses, textbooks and practice materials are separate from ACAC's fees and are optional. Because they come from different vendors, prices vary, and you should compare them against what the credential actually requires. Our full pricing breakdown separates issuer fees from optional spending.
Reading the Pass Ratio Carefully
ACAC's 2025 exam pass ratio report shows 31%, or 4 passes from 13 examinations. That figure is easy to misread. The report includes retakes and state-licensing-only examinations, and the cohort is very small. It therefore is not a first-attempt success probability for CMR candidates, and it should not be used to predict whether any individual will pass.
Staying Certified: Renewal Credits
Certification is valid for two years. Renewal costs USD 400 and requires 40 renewal credits (RCs). Under the current procedures, 10 are allocated to continued field activity and 30 come from professional-development hours. Supporting documentation is requested if you are audited, so keep certificates, attendance records and job documentation organized from the day you certify.
One source conflict is worth flagging: ACAC's issuer overview page for microbial remediation still mentions 20 professional-development hours per year, which differs from the current recertification procedures. When planning your cycle, follow the current procedures page and confirm with ACAC if your renewal date is near.
Roles, Employers and Earnings Evidence
Credential holders are typically found at remediation contractors, restoration firms, environmental consulting practices and facilities teams that manage mold and water-damage response. Relevant roles include remediation supervisor, project manager, lead technician and field estimator. Searching job postings for the exact phrase "Council-certified Microbial Remediator" and for ACAC will show how often employers name it directly. Our CMR jobs overview covers the role landscape.
On compensation, there is no reliable basis to claim that this certification, by itself, causes a pay premium. Pay in remediation varies with region, employer type, role and experience. A better approach is to evaluate real postings and ask employers whether the credential is required, preferred or simply helpful for bidding on certain projects. Our salary guide and ROI analysis take that evidence-based approach.
A Domain-Ordered Starting Plan
You do not need an elaborate method to begin. A sequence that follows how remediation jobs unfold tends to make the material stick, because each domain builds on the last. Use it as a starting scaffold and adjust to your weak spots. The CMR cheat sheet is helpful for last-pass review.
Principles, Standards and Water Damage
- Read the prescribed references' core chapters for Domains 1 to 3
- Pin down S500 water categories and classes first, since later domains assume them
Structural, Contents and HVAC Work
- Study Domain 4 and Domain 5 against S520 and the EPA guidance
- Practice explaining containment and removal decisions out loud
Documentation, Safety and Review
- Cover Domain 6 and Domain 7, including respirator selection logic
- Run timed question sets from our practice test site to rehearse the three-hour pace
Because the exam is closed book, practicing without references matters. Questions written in the style of our CMR practice tests help you find which domains need another pass. For help picking resources, our CMR training overview compares preparation options.
Frequently Asked Questions
It stands for Council-certified Microbial Remediator, a credential issued by the American Council for Accredited Certification (ACAC). The acronym is shared by unrelated credentials, so confirm any resource targets this specific one.
The exam has 100 multiple-choice questions with at least four choices each, three hours, closed book. The passing criterion is 75%, set by the certification board using modified Angoff.
No. A prep course is optional. What you do need is documented experience and education that satisfy one of the two eligibility routes, plus four project sheets and the required verifications.
Certification lasts two years. Renewal costs USD 400 and requires 40 RCs: 10 for continued field activity and 30 professional-development hours, with documentation available if audited.
No. NORMI issues its own separate credential, and its syllabus does not define the ACAC exam. Likewise, CMRS is a distinct ACAC designation with its own eligibility and exam details.