- What You Are Actually Studying For
- Exam Format and Delivery Rules
- Reading the Blueprint: Where the Points Live
- Domain-by-Domain Content to Master
- Prerequisites, Validity Windows and Timing
- A Domain-Weighted Study Sequence
- Exam-Day Mechanics and Retake Rules
- After You Pass: Certification and Renewal
- Frequently Asked Questions
- The RMI exam has 95 delivered questions: 85 scored plus 10 unscored trial items, with a two-hour limit.
- Implement Mitigation Installation Strategy carries 30% of the blueprint, more than any other domain.
- The exam fee is $125; initial certification and biennial renewal are $250 each, separate from training.
- Personal reference books are not allowed; SGM-SF-2023, MAH-2023, a calculator and formulas appear in-platform.
What You Are Actually Studying For
Before opening a single study resource, be precise about the credential. The Radon Mitigation Installer (RMI) credential is issued through the National Radon Proficiency Program (NRPP). It is the supervised installer credential: the person who physically installs mitigation systems under the oversight of an NRPP-certified Radon Mitigation Specialist (RMS) employed by the same company. It is not the RMS credential, not the RMP (measurement) credential, and not a state license. State licensing rules are a separate layer you must check on your own.
If you are still orienting yourself, the explainers on what RMI certification is and what RMI stands for cover the basics. This guide assumes you have decided to sit for the exam and want a plan built around the actual blueprint.
Exam Format and Delivery Rules
The delivery details have changed from older handbook language, so rely on current NRPP exam pages rather than outdated forum posts or PDFs that mention a different proctoring vendor.
| Item | Current Detail |
|---|---|
| Delivery | Certiverse, live remote proctoring |
| Questions delivered | 95 total |
| Scored items | 85 |
| Unscored trial items | 10 (not identified to you) |
| Time limit | Two hours |
| Exam fee | $125 |
| In-platform references | SGM-SF-2023, MAH-2023, calculator, formulas |
| Check-in | Photo ID, live proctor, room scan |
| Breaks | One bathroom break of up to five minutes |
Two practical consequences follow. First, because 10 of the 95 items are unscored trials you cannot distinguish from real questions, treat every question as if it counts. Second, two hours for 95 questions leaves roughly a minute and a quarter per item, so you cannot afford to spend several minutes hunting through a reference document on every question. For more on how the exam feels in practice, see how hard the RMI exam is.
Reading the Blueprint: Where the Points Live
The official outline has six content areas. The weights total 100%, and they are uneven enough that your study time should be uneven too.
| Domain | Weight |
|---|---|
| Domain 1: Communicate with the Client | 14% |
| Domain 2: Identify Radon Entry Points | 17% |
| Domain 3: Maintain Jobsite Safety | 15% |
| Domain 4: Implement Mitigation Installation Strategy | 30% |
| Domain 5: Perform Post-Installation Tasks | 17% |
| Domain 6: Operate in an Ethical and Professional Manner | 7% |
Domain 4 alone is nearly a third of the exam. Domains 2 and 5 together add another 34%. Ethics is the smallest slice at 7%, but it is also the most predictable and cheapest to master, so do not skip it. For a fuller breakdown of each area, read the complete guide to all six RMI content areas.
Domain-by-Domain Content to Master
The domain names are official; the bullet points below describe the kinds of competencies an installer-level exam in each area is built to test. Use your approved mitigation training materials and the in-platform standards to confirm specifics.
Domain 4: Implement Mitigation Installation Strategy (30%)
This is the core of the job and the core of the exam. Expect scenario questions that ask what you would do on a given house, not abstract definitions.
- Choosing and laying out active soil depressurization components for different foundation types
- Pipe routing, sizing, slope, support and condensation considerations
- Fan selection and placement, including exterior and attic placement tradeoffs
- Sealing of cracks, sumps, floor-wall joints and other openings
- Electrical, discharge point and monitoring (manometer) requirements for a finished system
- Working from the standards you can access in-platform rather than from memory alone
Domain 2: Identify Radon Entry Points (17%)
Before you can fix a house you must understand how radon gets in.
- Common entry routes: slab cracks, control joints, sumps, crawlspaces, block walls, utility penetrations
- How pressure differentials, stack effect and building characteristics drive soil gas entry
- Reading a foundation and recognizing what an inspection should look for
- Linking an observed condition to the appropriate mitigation approach
Domain 5: Perform Post-Installation Tasks (17%)
The job is not finished when the fan turns on.
- System checks and verification that the installation performs as designed
- Labeling, documentation and handoff of system information to the client
- Explaining operation, maintenance and what the client should monitor
- Understanding the relationship between installation work and follow-up testing
Domain 3: Maintain Jobsite Safety (15%)
Safety questions tend to reward careful reading rather than memorization.
- Hazard recognition in attics, crawlspaces, basements and confined or awkward spaces
- Personal protective equipment and safe handling of tools, ladders and electrical components
- Combustion appliance and backdrafting concerns when changing building pressures
- Dust, debris and material handling when drilling or cutting concrete
Domain 1: Communicate with the Client (14%)
Installers are the face of the company in someone's home.
- Setting expectations on scope, aesthetics, noise, cost and timeline
- Explaining what mitigation does and does not guarantee
- Handling concerns and documenting agreements clearly
- Knowing when to refer a question to the supervising RMS
Domain 6: Operate in an Ethical and Professional Manner (7%)
Small weight, easy points.
- Honesty in representing qualifications and work performed
- Operating within the limits of an installer credential and under required supervision
- Respecting client property, privacy and applicable codes and rules
- Understanding the Statement of Professional Responsibility you sign
Key Takeaway
Because the exam supplies SGM-SF-2023 and MAH-2023 in-platform, your goal is not to memorize every clause. Learn where topics live in those documents and practice answering from them quickly, so you spend seconds, not minutes, per lookup.
Prerequisites, Validity Windows and Timing
Many first-attempt failures are really paperwork and timing problems. Understand the pathway before you pay for anything. Full detail is in the RMI requirements guide; the essentials are:
- Measurement training: approved training of at least 12 hours
- Mitigation training: approved training of at least 20 hours
- Examination: a successful RMI exam result
- Statement of Professional Responsibility: signed
- Supervision: an NRPP-certified RMS employed by the same company
Two clocks are running once you start. Training certificates are usable for two years, and an examination result is usable for one year. That means you should not pass the exam and then sit on the result while hunting for a sponsoring company or supervisor. Line up your employer and supervisor early so your exam result does not expire before certification is complete.
If you are weighing the career side before committing, the RMI salary guide and the overview of RMI jobs describe who hires installers, typically radon mitigation companies, home-improvement and basement-systems contractors, and some builders and inspection-adjacent firms. Because you must be supervised by an RMS at the same company, your employer is usually part of your certification story from day one.
A Domain-Weighted Study Sequence
This is the one methodology section in this guide, and it is built around the blueprint rather than generic habits. The logic: front-load the heaviest and most scenario-driven domain, interleave the entry-point and post-installation domains because they are conceptually linked to it, and leave the cheap, memorizable areas for the final stretch. Adjust the length to your training schedule and experience.
Foundations and Domain 2
- Review your approved training notes on how radon enters buildings
- Sketch entry routes for slab, basement, crawlspace and sump foundations
- Skim the exam objectives in the Candidate Handbook, Appendix A
Domain 4 (30%)
- Walk through complete system designs for each foundation type
- Practice locating relevant sections of SGM-SF-2023 and MAH-2023 quickly
- Work calculator and formula problems until they are routine
Domains 5 and 3
- Study post-installation verification, labeling and documentation
- Review jobsite hazards, PPE and combustion appliance concerns
Domains 1 and 6, then timed practice
- Cover client communication and ethics
- Sit full-length timed sets mirroring the 95-question, two-hour format
- Review misses by domain and revisit the weakest one
Use the RMI practice tests for the timed work in the final week, and review misses by domain rather than by raw score so you know whether the problem is installation strategy, safety or something else. A one-page refresher such as the RMI cheat sheet is useful the night before, but it is a recap, not a substitute for working through scenarios.
Exam-Day Mechanics and Retake Rules
Because the exam is remotely proctored, your environment matters as much as your knowledge.
- Prepare the room. Expect a live proctor and a room scan. Clear your desk and walls of notes and unauthorized materials.
- Have photo ID ready. Identity verification is part of check-in.
- Do not bring personal reference books. The in-platform standards, calculator and formulas are what you get.
- Plan your break. One bathroom break of up to five minutes is permitted, so use the restroom beforehand.
- Pace yourself. Aim to move steadily through the 95 items, flagging time-consuming lookup questions to return to if the platform allows.
If things go wrong, there is a structure around retakes: a 30-day waiting period between attempts and a cap of four attempts in any 12-month period. That is workable but not forgiving, and each attempt costs the $125 exam fee. The practical takeaway is to treat your first sitting as the real one. Scheduling specifics are covered in the RMI exam dates guide.
After You Pass: Certification and Renewal
Passing the exam is one requirement, not the finish line. You still need the signed Statement of Professional Responsibility, qualifying training on file, and a supervising RMS at your company. Certification lasts two years.
Renewal requires eight Category I continuing education hours, including the applicable four-hour Standards Overview course, along with ethics compliance and current supervisor documentation. The renewal fee is $250. Supervision policies have been updated in recent months, so check NRPP's current supervisory guidance rather than relying on what a coworker remembers from a prior cycle.
For a broader picture of the credential itself, see the pages on RMI certification and RMI training.
Key Takeaway
Plan the whole pathway, not just exam day: training certificates last two years, exam results last one year, and certification requires a supervising RMS at your company. Sequence your training, exam and employment so none of those windows lapse.
Frequently Asked Questions
You will see 95 delivered questions. Of those, 85 are scored and 10 are unscored trial items. The trial items are not marked, so answer every question carefully. You have a two-hour testing limit.
No. Personal reference books are not permitted. The exam platform provides SGM-SF-2023, MAH-2023, a calculator and formulas. Because the exam is live-proctored with a room scan, practice using those in-platform tools beforehand.
Domain 4, Implement Mitigation Installation Strategy, at 30%. Then give strong attention to Identify Radon Entry Points and Perform Post-Installation Tasks at 17% each, followed by Maintain Jobsite Safety at 15% and Communicate with the Client at 14%. Ethics is only 7% but is a good place to secure easy points.
You must wait 30 days before retaking, and you can make at most four attempts within 12 months. Each attempt requires the $125 exam fee, so it pays to prepare thoroughly before your first sitting.
Not by itself. Certification also requires the approved measurement and mitigation training, a signed Statement of Professional Responsibility, the $250 initial certification fee, and supervision by an NRPP-certified RMS employed by your company. Keep in mind that exam results remain usable for one year and training certificates for two. State licensing, where required, is separate.
With a clear view of the six domains, the in-platform tools and the pathway around them, you can prepare deliberately instead of guessing. Build your plan around installation strategy, practice with the supplied standards, and take timed sets on the RMI practice test platform so exam day feels familiar.