- Which RMS This Cheat Sheet Covers
- The Version Conflict You Must Know First
- Six-Domain Blueprint at a Glance
- Legacy Section Weights (Two Separate Distributions)
- Technical Core: What to Master
- Fees, Testing Provider and Exam-Day Rules
- Prerequisites and Renewal Side by Side
- Sequencing Your Review by Domain
- Frequently Asked Questions
- This is the NRPP Radon Mitigation Specialist (RMS) credential, not NRSB's measurement credential or the Canadian C-NRPP.
- The announced six-domain blueprint weights Diagnostics 28%, System Design 24%, and ASD Mitigation System Installation 23%.
- The live operational page says 165 questions; the May 2026 update says 175. Confirm your form before booking.
- Exam fee is USD 175 per attempt, plus USD 275 for initial two-year certification.
Which RMS This Cheat Sheet Covers
"RMS" is a crowded acronym, so start with the identity check. Everything below concerns the Radon Mitigation Specialist (RMS) credential governed by the National Radon Proficiency Program (NRPP). It is not the Canadian C-NRPP, not the National Radon Safety Board's Radon Measurement Specialist, and not the Radon Mitigation Installer credential. If you are still sorting out terminology, see our explainers on what RMS is and what RMS stands for.
This page is built as a quick-reference review. Where the public record is unsettled, it says so rather than smoothing over the conflict. For a deeper plan after you finish here, pair it with the RMS study guide, and when you want to test recall, take a timed run on the main practice test site.
The Version Conflict You Must Know First
The single most important fact on this cheat sheet is that two descriptions of the exam are in circulation, and no verified activation notice says which one a current booking receives.
| Item | Live operational page (effective Oct 1, 2024) | May 2026 NRPP update (announced revision) |
|---|---|---|
| Total questions | 165 | 175 |
| Scored questions | 150 (one point each) | 160 |
| Unscored trial/pilot questions | 15, not identified to you | 15 |
| Testing time | Three hours | Three hours |
| Required training | 16-hour measurement course plus 24-hour mitigation course | 32-hour mitigation course including measurement content, plus lab and field experience |
| Renewal CE | 12 hours | 24 hours |
For more on how this affects difficulty, see how hard the RMS exam is, and for scheduling mechanics see RMS exam dates.
Six-Domain Blueprint at a Glance
The six domains below reproduce the latest announced official blueprint (labeled "2025 RMS" in the May 2026 NRPP Credentialing Updates). The weights total 100%. They are examination domains, not course-hour allocations, and they are not asserted to be the form delivered to every candidate today.
| Domain | Weight | Priority |
|---|---|---|
| 1. General | 4% | Light review |
| 2. Inspection | 13% | Moderate |
| 3. Diagnostics | 28% | Highest |
| 4. System Design | 24% | High |
| 5. ASD Mitigation System Installation | 23% | High |
| 6. Post-mitigation | 8% | Light to moderate |
Three domains (Diagnostics, System Design and Installation) carry 75% of the blueprint between them. A candidate who is weak in any one of them has little room to compensate elsewhere. The RMS exam domains guide goes deeper on each content area.
Legacy Section Weights (Two Separate Distributions)
The 2021 issuer launch explicitly included installer competencies inside the RMS examination. That older structure is why you will see two separate percentage lists in older materials. They are two independent 100% distributions, not fourteen percentages that add up across one exam.
Legacy installer-competency sections
- Communicate with the Client (14%)
- Identify Radon Entry Points (17%)
- Maintain Jobsite Safety (15%)
- Implement Mitigation Installation Strategy (30%)
- Perform Post-Installation Tasks (17%)
- Operate in an Ethical and Professional Manner (7%)
Legacy specialist sections
- Communicate Basic Radon Science (9%)
- Evaluate Pre-Mitigation Measurement (8%)
- Design Radon Mitigation System (25%)
- Validate Post-Installation Data (12%)
- Troubleshooting System Problems / Implement Corrective Actions (17%)
- Develop / Maintain Worker Health and Safety Plan (8%)
- Maintain Mitigation Quality Assurance Plan (12%)
- Operate in an Ethical/Professional Manner (9%)
The May 2026 comparison describes the older form as two parts: Part 1 with 85 scored plus 10 pilot items and Part 2 with 65 scored plus five pilot items. That helps explain why the specialist task counts total 65 rather than the whole exam's 150 scored questions. The older handbook's RMS table labels 150 questions without clearly separating those denominators, and that limitation remains. No combined weighting or per-domain question count is published, so avoid any study resource that claims one.
Technical Core: What to Master
Whichever form you sit, the technical center of gravity is the same: diagnose a building, design a system that will work, and install it correctly. These are the topics worth drilling.
Diagnostics (28% in the announced blueprint)
Diagnostics: the largest domain
Diagnostics is about understanding how a specific building interacts with soil gas before committing to a design.
- Pressure-field extension: know what it means to extend suction beneath a slab, how communication is checked, and what weak or uneven extension implies for suction-point placement.
- Reading the building: foundation type, sub-slab materials, penetrations, and stack or mechanical effects that influence entry and system performance.
- Interpreting pre-mitigation data: the legacy "Evaluate Pre-Mitigation Measurement" competency still shows up conceptually as you judge whether test results justify and inform a design.
System Design (24%)
Design and sizing
Expect calculation-flavored thinking here. The exam environment provides an on-screen calculator and formula resources, so the skill being tested is knowing which relationship applies, not memorizing constants.
- Radon fan and pipe sizing: match fan performance to expected airflow and resistance; understand how pipe diameter, length and fittings affect friction loss.
- Suction-point strategy: number and location of points relative to diagnostic findings.
- Standards fluency: the exam supplies ANSI/AARST standards (current supplied standards are SGM-SF-2023 and MAH-2023), so practice navigating them quickly rather than recalling clauses from memory.
ASD Mitigation System Installation (23%)
Active soil depressurization in the field
- Sealing and detailing: sump pits, slab cracks, penetrations and block-wall openings.
- Routing, support and discharge of vent piping, and fan placement that keeps the pressurized portion outside conditioned space.
- Electrical and labeling considerations, plus the jobsite safety habits carried over from the legacy installer sections.
Inspection, General and Post-mitigation (25% combined)
Inspection (13%) covers evaluating a structure and identifying radon entry routes; General (4%) covers foundational radon science and professional conduct; Post-mitigation (8%) covers validating that the installed system is working, including verification data and corrective action when it is not. These are smaller blocks, but they are also where careless candidates lose easy points.
Fees, Testing Provider and Exam-Day Rules
| Item | Operational detail |
|---|---|
| Exam fee | USD 175 per attempt |
| Initial certification | USD 275 for two years |
| Exam plus initial certification | USD 450, before training and other costs |
| Renewal fee | USD 275 |
| Member discount on exam fee | None published |
| Testing provider | Certiverse with live remote proctoring |
The separately advertised online study guide is USD 25 for 60-day access and free to members; that is a study product, not an exam-fee discount, and its paid contents were not reviewed for this article. These are operational prices, not a confirmed tariff for the revised program. The full breakdown lives in the RMS certification cost guide.
Exam-day rules to know cold
- Remotely monitored and recorded, with photo ID and a room scan required.
- Supplied: ANSI/AARST standards, an on-screen calculator and formula resources.
- Prohibited: outside books, notes and personal calculators. This is not unrestricted open-book testing.
- One break of up to five minutes, with proctor permission.
- Purchase must be scheduled and completed within 30 days.
- Retakes require a 30-day wait, with no more than four attempts per 12 months.
- Exam Conduct Requirements are version 5, revised April 25, 2025.
Passing Score and Pass Rate: What Is Not Public
The handbook describes a criterion-referenced standard for competent performance set through expert judgment. A current numeric RMS cutoff is not publicly specified, and no credential-specific pass rate was verified. Do not import another organization's percentage threshold, and do not treat training-provider success claims as exam statistics. Questions are delivered on a computer, but the retrieved current pages do not spell out a complete answer-format specification; older multiple-choice guidance is historical. Our passing score and pass rate pages explain what can and cannot be said.
Prerequisites and Renewal Side by Side
| Topic | Live operational route | Announced revision |
|---|---|---|
| Training | NRPP-approved 16-hour measurement course plus 24-hour mitigation course; coursework valid two years | 32-hour mitigation course including requisite measurement content; separate 16-hour measurement course not required |
| Experience | No current degree, employment-hour or reference minimum verified | Lab and field experience; no field-hour minimum or delivery method published |
| After passing | Apply within one year; agree to ethics/terms; QA/QC attestation and ID photo | Details not finalized |
| Certification term | Two years | Two years (per available materials) |
| Renewal CE | 12 hours: at least eight Category I, no more than four Category II | 24 hours including four standards-review hours; up to four Category II and up to four nontechnical credits allowed |
Two points trip people up. First, passing the exam alone does not confer certification; you must complete the application steps. Second, state licensing is separate from NRPP certification, so check your jurisdiction's own rules. Under the live route, the mandatory four-hour mitigation standards overview is included within the 12 CE hours, not added on top. The announced program also introduces work-sample or experience documentation, but no number of installations or field hours has been published. See RMS requirements for eligibility detail.
Key Takeaway
Preserve the 12-versus-24 CE conflict until you confirm which renewal cycle applies to you. When in doubt, ask NRPP which program your certification date falls under before you plan CE purchases.
Sequencing Your Review by Domain
Because the blueprint is unevenly weighted, order your review by points at stake rather than by textbook chapter. This is the only study-method advice on this page, and it is tied directly to the domain weights.
Diagnostics (28%)
- Pressure-field extension and communication checks
- Building-type and entry-route reasoning
System Design (24%)
- Fan and pipe sizing with the on-screen calculator workflow
- Practice locating relationships in ANSI/AARST standards
ASD Installation (23%)
- Sealing, routing, discharge and fan placement
- Jobsite safety and professional conduct items
Inspection, General, Post-mitigation (25%)
- Verification data and corrective actions
- Full timed practice under three-hour conditions
Finish with a full-length timed run so the three-hour pace and the standards-lookup habit are automatic. The RMS study guide expands this plan, and you can drill questions on the RMS Exam Prep practice test.
Where the Credential Fits Professionally
No credential-specific salary premium was verified, and occupational salary estimates from job boards are not evidence that certification causes higher pay. What can be said qualitatively: the RMS is the NRPP route for professionals who diagnose, design and install radon mitigation systems, and some jurisdictions layer their own licensing on top. For a measured discussion, read the RMS salary guide and the ROI analysis.
Frequently Asked Questions
It depends on the active form. The live operational page states 165 total (150 scored plus 15 unscored trial questions); the May 2026 NRPP update specifies 175 (160 scored plus 15 pilot). Testing time is three hours in both. Confirm which form your booking uses.
In the announced six-domain blueprint, Diagnostics is largest at 28%, followed by System Design at 24% and ASD Mitigation System Installation at 23%. Inspection is 13%, Post-mitigation 8%, and General 4%.
The published operational figures are USD 175 per exam attempt and USD 275 for the initial two-year certification, totaling USD 450 before training and other costs. Renewal is USD 275. No member exam-fee discount is published.
No. Outside books, notes and personal calculators are prohibited. The remote exam supplies ANSI/AARST standards, an on-screen calculator and formula resources, and you may take one break of up to five minutes with proctor permission.
NRPP describes a criterion-referenced standard for competent performance set by expert judgment. A current numeric RMS cutoff is not publicly specified, so avoid sources that quote one without citing NRPP.