10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free RMS questions are organized by exam domain, so you can see how each part of the Radon Mitigation Specialist (RMS) blueprint is tested. Reveal the answer and explanation under each question.
A nonsmoking couple with a toddler receives a valid, representative long-term radon result of 3.1 pCi/L. They ask whether being below EPA's 4 pCi/L action level means there is no reason to reduce it. The accurate response is:
Correct answer: C - Consider reducing radon; nonsmokers still face risk at concentrations below 4 pCi/L.
A home-sale report lists 1.2 pCi/L for a finished basement and 5.8 pCi/L for an occupied slab-on-grade addition, then presents 3.5 pCi/L as the home's overall result. A qualifying continuous radon monitor tested each location simultaneously, and all MAH-2023 test conditions and quality checks were satisfactory. What needs correction in the report?
Correct answer: D - The locations must be reported separately; the elevated addition result cannot be canceled by the basement result.
For an MAH-2023 time-sensitive home-sale test, a technician selects an approved electronic integrating device that reports a deployment average but cannot retrieve hourly readings. The location, building conditions, and proposed exposure duration are compliant. The deployment can meet the time-sensitive configuration by:
Correct answer: A - Using a second approved passive detector 5 inches away, with both exposed simultaneously for the full period.
The riser manometer on an active soil depressurization system stays at its established operating reading when a kitchen exhaust hood is switched on. At a remote test port, however, P_subslab minus P_indoor changes from −3 Pa with the hood off to +1 Pa with it on. The radon fan runs continuously and other conditions are unchanged. With the hood running, the measurements indicate that:
Correct answer: B - Subslab pressure exceeds indoor pressure at that port, so the local pressure barrier is lost.
During diagnostic suction testing, an uncovered sump is open to the basement. Airflow is 130 cfm, but remote subslab ports show little response. Fitting an airtight temporary cover reduces flow to 70 cfm and produces consistent subslab pressure below indoor pressure at those ports. Pump operation and drainage are unaffected. Which permanent change does this comparison support?
Correct answer: B - Fit an airtight, serviceable sump cover that preserves drainage, then verify the completed pressure field.
A home's U-tube manometer shows equal fluid levels even though the radon fan is running. A calibrated digital manometer connected directly to the same riser tap repeatedly reads the documented operating suction of 0.85 in. WC. Both instruments reference the same basement air. Reconnecting the U-tube with its usual tubing again produces a zero reading. Where should troubleshooting begin?
Correct answer: D - Inspect the permanent indicator and its pressure connection for leakage, blockage, or incorrect fluid condition.
Diagnostics establish a required airflow of 75 cfm with 0.60 in. WC of vacuum at the pickup. All additional losses in the permanent duct and fittings total 0.25 in. WC at that flow, on the same pressure reference. Three otherwise suitable fans have these ratings: X-220 cfm free-air flow and 0.70 in. WC at 75 cfm; Y-150 cfm free-air flow and 0.95 in. WC at 75 cfm; Z-280 cfm free-air flow and 0.50 in. WC at 75 cfm. Select the fan with sufficient capacity at the required duty.
Correct answer: D - Fan Y; its available pressure at 75 cfm exceeds the combined pickup and duct requirement.
A dirt-floor crawlspace has safe access, adequate working height, and an atmospherically vented gas water heater. A contractor proposes exhausting the crawlspace air directly to avoid installing a soil membrane. A preliminary spillage check finds no problem. Under SGM-SF-2023, which design judgment is justified?
Correct answer: A - Reject direct airspace suction here; evaluate sealed submembrane suction that preserves combustion safety.
During commissioning, a natural-draft water heater spills flue gases whenever the new soil-depressurization fan runs. Switching the fan off restores the draft. What takes priority before this mitigation system is returned to service?
Correct answer: A - Deactivate the system, notify the occupants, and obtain qualified evaluation and correction of the spillage.
An ASD system uses 4-inch-ID duct piping throughout. Its outlet points upward at 40° from vertical, 12 feet above grade and 24 inches above a flat roof. A neighboring building's soffit vent is 16 feet from the outlet, directly along the outlet's centerline. All other applicable clearances are satisfied. How does that vent affect compliance with SGM-SF-2023?
Correct answer: C - The outlet needs relocation or redirection to clear the 20-foot straight-line exhaust zone.
The RMS exam also covers these domains. Drill them in the full free practice test:
The full bank has 1,020 more RMS questions with explanations.
Continue in the free practice test →
View plans