- What This Cheat Sheet Covers (and What It Doesn't)
- Exam Logistics at a Glance
- The Six-Domain Blueprint and Its Weights
- Domain-by-Domain Quick Review
- Fees, Validity Windows and Renewal
- Prerequisites and Supervision
- Test-Day Rules That Trip People Up
- A Domain-Weighted Review Sequence
- Where Certified Installers Work
- Frequently Asked Questions
- The Radon Mitigation Installer (RMI) exam delivers 95 questions in two hours: 85 scored and 10 unscored trial items.
- Implement Mitigation Installation Strategy carries 30% of the blueprint, more than any other domain.
- Exam fee is $125; initial certification and biennial renewal are $250 each, separate from training costs.
- Training certificates are usable for two years, while exam results stay usable for one year.
What This Cheat Sheet Covers (and What It Doesn't)
This page condenses the facts that matter most for the Radon Mitigation Installer (RMI) credential issued through the National Radon Proficiency Program (NRPP). It is built for the final stretch of preparation: the week you want to verify that the numbers, windows and domain weights in your head match the published requirements.
Scope matters here. This sheet covers the supervised installer credential only. It does not cover the Radon Mitigation Specialist (RMS) or Radon Measurement Professional (RMP) credentials, and it does not replace your state's licensing rules, which are a separate layer of requirements. If you are still deciding whether the credential fits your career, start with What Is RMI Certification? and come back once you are committed.
Exam Logistics at a Glance
The format is straightforward once you separate what you see from what counts. Here is the current delivery picture in one table.
| Item | Current Detail |
|---|---|
| Delivery | Certiverse, live remote proctoring |
| Questions delivered | 95 total |
| Scored items | 85 |
| Unscored trial items | 10 (in effect since October 1, 2024) |
| Time limit | Two hours |
| Exam fee | $125 |
| Identification | Photo ID required |
| Environment checks | Live proctor and room scan |
| Breaks | One bathroom break, up to five minutes |
| Retake rules | 30-day wait; maximum four attempts in 12 months |
The ten unscored trial items are indistinguishable from scored ones, so treat every question as if it counts. Do not burn minutes trying to guess which ones are experimental. Two hours for 95 questions leaves you a little over a minute per item, which is comfortable if you do not stall on calculation questions. For a deeper look at how the format feels, see How Hard Is the RMI Exam?.
Passing standard: what is and is not published
Passing follows the issuer's competency standard. This cheat sheet deliberately does not assign a numerical passing score, because none is supported in the published material. Be wary of any site that quotes a specific cut percentage as fact. The related article RMI Passing Score 2026 explains what can and cannot be said about scoring.
The Six-Domain Blueprint and Its Weights
The official exam objectives appear in Appendix A of the NRPP Candidate Handbook (PDF pages 19-20). The six headings and their percentages total 100%. This is the verified published blueprint for the installer exam, not a claimed 2026 revision, and no outline from another NRPP credential is substituted for it.
| Domain | Weight |
|---|---|
| 1. Communicate with the Client | 14% |
| 2. Identify Radon Entry Points | 17% |
| 3. Maintain Jobsite Safety | 15% |
| 4. Implement Mitigation Installation Strategy | 30% |
| 5. Perform Post-Installation Tasks | 17% |
| 6. Operate in an Ethical and Professional Manner | 7% |
Domain-by-Domain Quick Review
The blocks below summarize the kinds of competencies each domain tests. They describe the type of knowledge expected for a supervised installer; confirm specifics against your approved mitigation training materials and the standards the exam references.
Domain 1: Communicate with the Client (14%)
This domain tests whether you can explain the work, the system and the limits of what mitigation promises, in plain language and in writing.
- Setting accurate expectations about what a system does and what it cannot guarantee
- Explaining system components, operation and the homeowner's maintenance role
- Documenting agreements, changes to scope and instructions left with the client
- Responding professionally to concerns without overstating health claims
Domain 2: Identify Radon Entry Points (17%)
Before you design a system, you must read the building. Expect scenario questions about how soil gas enters a structure and how foundation type changes your approach.
- Common entry routes: slab cracks, joints, penetrations, sumps, drains and block walls
- How foundation types (slab-on-grade, basement, crawlspace) shape the diagnosis
- Pressure relationships and the stack effect that drive soil gas into a home
- Building features and obstructions that affect system routing
Domain 3: Maintain Jobsite Safety (15%)
Installation work involves cutting concrete, working at height, handling electrical connections and sometimes entering confined spaces. Safety questions are practical and procedural.
- Personal protective equipment and dust control when drilling or coring slabs
- Electrical safety for fan wiring and disconnects
- Ladder, roof and attic work hazards
- Combustion appliance and backdrafting awareness during installation
Domain 4: Implement Mitigation Installation Strategy (30%)
This is the heart of the exam. It covers the physical installation of active soil depressurization-type systems and the decisions that make them work or fail.
- Selecting suction point locations and sizing pipe appropriately
- Fan selection, placement and exhaust discharge requirements
- Sealing of openings, sump covers and other pathways
- Pipe routing, support, slope and condensation drainage
- System labeling, monitoring devices such as manometers, and electrical integration
- Using the in-exam calculator and the formulas provided on the platform
Domain 5: Perform Post-Installation Tasks (17%)
The job is not finished when the fan turns on. This domain checks that you verify performance and leave the client with complete documentation.
- Checking system operation, vacuum readings and leak points after startup
- Confirming that post-mitigation testing is arranged appropriately
- Providing operation and maintenance instructions and system documentation
- Recordkeeping and follow-up procedures
Domain 6: Operate in an Ethical and Professional Manner (7%)
Small in weight, but rich in judgment questions. It ties directly to the Statement of Professional Responsibility you must sign as part of certification.
- Honest representation of credentials and of your supervisory arrangement
- Avoiding conflicts of interest and misleading claims
- Operating within the scope of an RMI and under the required supervision
- Following applicable codes, standards and state requirements
Key Takeaway
Questions in Domains 1 and 6 often have two defensible-sounding answers. Choose the one that is most honest, most documented and most consistent with supervision requirements. Domain 4 questions tend toward the technical, so know your standards and formulas cold.
Fees, Validity Windows and Renewal
Money and calendar rules cause more avoidable problems than any technical topic. These figures reflect the fee schedule effective January 1, 2025, and they are separate from the cost of your training courses.
| Item | Amount or Window |
|---|---|
| Exam fee | $125 |
| Initial certification | $250 |
| Biennial renewal | $250 |
| Training certificate validity | Usable for two years |
| Exam result validity | Usable for one year |
| Certification term | Two years |
Notice the interplay between the two validity windows. If you pass the exam but delay completing your other prerequisites past one year, the result expires and you would need to sit the exam again. Likewise, aging training certificates can lapse after two years. Plan your sequence so that nothing expires before the certification is issued. A full cost walk-through lives in RMI Certification Cost 2026.
Renewal checklist
- Eight Category I continuing education hours within the two-year cycle
- The applicable four-hour Standards Overview course, which counts toward those hours
- Ethics compliance
- Current supervisor documentation on file
Prerequisites and Supervision
The exam is one piece of a larger eligibility package. The full requirements are laid out in RMI Requirements 2026: Eligibility, Prerequisites & How to Qualify, but the essentials fit in a short list.
- Approved measurement training of at least 12 hours
- Approved mitigation training of at least 20 hours
- A successful RMI examination result
- A signed Statement of Professional Responsibility
- Supervision by an NRPP-certified RMS employed by the same company
Test-Day Rules That Trip People Up
Remote proctoring adds a layer of procedure that has nothing to do with radon. Candidates who ignore it risk a stressful start or a terminated session.
- Photo ID: have an acceptable government-issued photo ID ready before check-in.
- Room scan: the live proctor will have you show your testing space. Clear your desk of notes, books and extra devices.
- One break only: a single bathroom break of up to five minutes is permitted. Use the restroom before you log in.
- No personal references: the platform supplies SGM-SF-2023, MAH-2023, a calculator and formulas. This in-platform access does not permit bringing your own reference books.
Because the standards documents are provided, your preparation should emphasize navigating them quickly rather than memorizing every clause. Practice locating a topic in SGM-SF-2023 and MAH-2023 under time pressure. If you want realistic timed repetition, try the practice questions on the main RMI practice test site.
A Domain-Weighted Review Sequence
If you have roughly four weeks, sequence your review by weight and by dependency rather than by chapter order. Diagnosis (Domain 2) should come before installation (Domain 4) because system design decisions depend on understanding entry routes. For a broader preparation framework, see the RMI Study Guide 2026.
Diagnosis and Safety
- Domain 2: entry routes, foundation types, pressure relationships
- Domain 3: PPE, electrical, dust and combustion appliance hazards
Installation Core, Part One
- Domain 4: suction points, pipe routing, sealing
- Practice with the formulas and calculator you will have in-platform
Installation Core, Part Two and Closeout
- Domain 4: fan selection, discharge, labeling, monitoring
- Domain 5: startup checks, documentation, post-mitigation testing
People, Ethics and Full Timing
- Domains 1 and 6: client communication scenarios and professional-conduct judgment
- Two timed passes at 95 questions inside a two-hour limit
Where Certified Installers Work
Because RMIs work under an NRPP-certified RMS at the same company, the typical employer is a radon mitigation contractor. That includes dedicated radon firms as well as home-services and construction businesses that offer mitigation alongside other work. Your day-to-day tasks usually mirror the exam domains: assessing a foundation, installing the system, verifying performance and walking the client through it.
Pay varies widely by region, employer type and experience, so this sheet does not quote figures. For market context, read RMI Salary Guide 2026 and RMI Jobs, and weigh them against your own situation in Is the RMI Certification Worth It?.
Frequently Asked Questions
The exam delivers 95 questions, of which 85 are scored and 10 are unscored trial items. You cannot tell which are which, so answer every question carefully. You have a two-hour testing limit.
Implement Mitigation Installation Strategy is weighted at 30%, the largest share of the blueprint. Domains 2 and 5 each carry 17%. Spend your deepest study time on Domain 4, then make sure the mid-weight domains are solid.
No. The platform provides SGM-SF-2023, MAH-2023, a calculator and formulas in-exam. Personal reference books are not permitted, and a proctor will scan your room before the session begins.
You must wait 30 days before a retake, and you can make at most four attempts in a 12-month period. Each attempt requires the exam fee again, so a structured review beforehand is the cheaper path.
Yes. Training certificates are usable for two years, and an exam result is usable for one year. Coordinate your timeline so both are still valid when you submit your certification application. For more on timing, see RMI Exam Dates 2026.
Keep this sheet beside your notes during the final week, and recheck the issuer's live pages for any change to fees, supervision policy or delivery details before test day. For questions about what the credential means and how it fits into radon work generally, What Is RMI? provides background.