What Is RMI Certification?

What the RMI Credential Actually Is

In the radon industry, RMI stands for Radon Mitigation Installer. It is the entry-level mitigation credential for people who physically install radon reduction systems in homes and buildings: drilling slabs, sealing foundation openings, running vent pipe, mounting fans and verifying that a system performs as designed. If you have seen the acronym attached to other fields, set those meanings aside. Everything on this page concerns the radon installer certification and nothing else.

The credential signals that an installer has completed approved training, passed a standardized examination, and agreed to a professional code of conduct. It is a supervised certification, meaning the installer operates under a more senior certified professional rather than as an independent mitigation contractor. That distinction shapes almost everything about how the credential is earned and used, and it is why this article keeps returning to supervision.

For quick definitional background, our short explainers cover what RMI is and what RMI stands for. This article goes further into how the certification works end to end.

Who Issues It and What It Covers

The credential is administered by the National Radon Proficiency Program (NRPP). NRPP publishes the candidate handbook, defines the exam objectives, runs the examination program, and sets renewal conditions. The exam objectives referenced in this article come from the NRPP Candidate Handbook (document 3-007-4 V7, revised May 4, 2023, Appendix A), which lists six content areas and their percentage weights totaling 100%.

It helps to be precise about scope. This article covers the supervised installer credential only. It does not cover the Radon Mitigation Specialist (RMS) credential, the Radon Measurement Professional (RMP) credential, or any state licensing program. Those are separate pathways with their own requirements, and mixing them up is a common source of confusion for newcomers.

The Path From Training to Certificate

Becoming a certified installer is a sequence, not a single event. The documented prerequisites are:

1. Measurement training of at least 12 hours from an approved provider.
2. Mitigation training of at least 20 hours from an approved provider.
3. Passing the RMI examination.
4. A signed Statement of Professional Responsibility.
5. Supervision by an NRPP-certified RMS employed by the same company.

Timing matters because paperwork expires. Training certificates remain usable for two years, and examination results remain usable for one year. If you pass the exam but delay assembling the remaining pieces, your result can lapse and you would need to retake the test. Plan the whole chain, from classroom hours through employer supervision, before you pay for an exam seat. Our RMI requirements guide walks through eligibility in more detail, and the RMI training overview explains how to choose a provider.

How the RMI Exam Is Delivered

The examination is delivered through Certiverse with live remote proctoring. Since October 1, 2024, each exam presents 95 questions: 85 scored items plus 10 unscored trial items used to evaluate future questions. You will not know which items are unscored, so treat every question as if it counts. The testing limit is two hours.

Some details candidates often overlook:

• Identity and environment: You need photo ID, a live proctor connection and a room scan before starting.
• Breaks: One bathroom break of up to five minutes is permitted.
• In-platform resources: The exam provides the SGM-SF-2023 and MAH-2023 documents, along with a calculator and formulas, inside the testing platform. This does not mean you may bring personal reference books.
• Retakes: A 30-day wait applies between attempts, with at most four attempts in 12 months.

Because the standards documents are available during the test, rote memorization of every clause is less valuable than knowing where things live and how to apply them. Practice navigating reference material quickly. Timed practice at our RMI practice test site helps you rehearse pacing against a two-hour clock. For scheduling specifics, see RMI exam dates and scheduling.

What about the passing score?

NRPP applies its issuer competency standard to determine a pass. This article does not assign a numerical cut score, because none is published here as a verified figure. Our passing score explainer covers what is and is not known, and the pass rate analysis discusses why public data on outcomes is limited.

The Six Exam Domains in Detail

The blueprint divides the exam into six domains. Weights tell you where scored questions concentrate, which should drive how you allocate study hours. For a full domain-by-domain walkthrough, see our complete guide to all six content areas.

The two lighter domains, Communicate with the Client (14%) and Operate in an Ethical and Professional Manner (7%), are easy to underestimate. Together they make up 21% of the exam, which is more than Domain 2 alone. Candidates with strong field skills sometimes lose points on scenario questions about client conversations or professional responsibility because they never reviewed the Statement of Professional Responsibility language.

Fees, Validity Windows and Renewal

Costs are modest compared with many trade credentials, but they stack. Under the fee schedule effective January 1, 2025:

These amounts are separate from training tuition, which varies by provider. A retake means paying the exam fee again, so preparing well the first time is also a financial decision. See the full RMI certification cost breakdown for budgeting guidance.

Renewal requirements

Certification lasts two years. To renew, you need eight Category I continuing education hours, which must include the applicable four-hour Standards Overview course. You also need to satisfy ethics compliance and provide current supervisor documentation. Because renewal depends on documented supervision, a job change can complicate things: confirm your new supervising RMS and paperwork before your renewal date arrives.

Supervision, State Rules and Who Hires

The defining feature of this credential is supervision. An installer must work under an NRPP-certified RMS employed by the same company. NRPP has issued supervision policy updates, so confirm current expectations on its website rather than relying on older forum posts or training handouts.

State licensing is a separate layer. Some states regulate radon professionals through their own programs with their own requirements, and those rules are independent of NRPP's. Check your state's radon office before assuming that holding the installer credential alone authorizes you to work there.

Who hires certified installers

Typical employers are radon mitigation companies, which employ installers under a certified RMS. Other employers can include home inspection and testing firms that offer mitigation as an add-on service, and general contractors or foundation and waterproofing contractors that have added radon work. Because the credential requires employer-based supervision, the practical route usually begins with a job, or at least an employer relationship, rather than a purely solo effort. Our pages on RMI jobs and the RMI salary guide discuss the employment side, and the ROI analysis weighs costs against career benefits.

Sequencing Your Prep Around the Blueprint

You do not need an elaborate method here. The blueprint itself suggests the order. Start with the domain that carries the most weight and builds the vocabulary for the others, then layer in the rest. A compact plan might look like this:

For a deeper approach, read the RMI study guide, keep the RMI cheat sheet handy for last-minute review, and check how hard the exam really is to calibrate your timeline. When you are ready to test your recall, take a practice test under timed conditions, and revisit the domain where you miss the most questions.

Frequently Asked Questions

For more on the credential's basics, you can also browse our overviews of RMI certification and what RMI certification is, then move on to the requirements and cost guides to plan your own path.