Radon Test Preparation Checklist: Before, During, and After Testing

Start by naming the decision the test must support

Write one sentence at the top of your notes: this test is for ordinary household screening, a home purchase, a planned basement conversion, or checking an installed mitigation system. Those purposes are not interchangeable. CDC identifies renovations and changes that increase time spent on a lower level as reasons to test. For a transaction, ask the responsible tester which protocol applies before choosing the date or room.

This checklist assumes you already have a device or testing appointment. It does not rank kits or decide which model to buy. If that choice is still unresolved, use our radon test-kit guide first. For preparation, the useful deliverable is a complete test record that another person can understand without guessing what happened in the house.^[3][2]

Read the entire instruction sheet before opening anything

Find the required exposure period, activation method, placement directions, expiration information if provided, laboratory address, registration requirements, and return deadline. A charcoal kit and a digital monitor do not share one universal start procedure. Short-term testing can cover different durations; use the instructions for the actual device rather than assuming every kit runs for two days.

Prepare the administrative pieces while the detector remains unopened: a pen, calendar reminders, device identification, laboratory contact details, and a place to store the report. Check who will be present at the finish. If you cannot complete the paperwork or arrange return shipment on the intended day, choose another start date instead of trying to reconstruct the timing later.^[3][4]

• Record the kit or monitor identification exactly as printed.
• Photograph the instructions so they remain available after the return package is sealed.
• Write down the laboratory’s question channel before the test begins.

Choose the room and a stable placement location

EPA’s ordinary homeowner guidance places a test on the lowest regularly lived-in level, in a frequently used room rather than a kitchen or bathroom. Its citizen guide specifies at least 20 inches above the floor, away from drafts, exterior walls, high heat, and high humidity. Follow the device instructions and any applicable measurement protocol if they require a more specific location.

For a purchase, the relevant level may instead be the lowest area that could be used regularly, even if the current owner rarely enters it. Decide that question with the tester. Mark the chosen spot in your notes, photograph its surroundings, and explain to everyone at home that the device must remain there. A convenient shelf is not suitable merely because it keeps the kit out of sight.^[1][2]

Arrange closed-house conditions without compromising safety

For EPA’s two- or three-day short tests, windows and exterior doors should be closed at least 12 hours before starting and kept closed during the test, apart from ordinary entry and exit. Do not treat this as a rule only for the room containing the detector. Avoid scheduling these very short tests during unusually severe storms or unusually high winds.

Normal heating and cooling need not simply be switched off. EPA distinguishes recirculating equipment from equipment that brings outside air inside, and an existing radon-reduction system should remain operating. If you cannot identify how a ventilation system works, ask the tester rather than changing its controls. Never block combustion-air openings or compromise safe temperatures to preserve a test; pause planning and obtain situation-specific directions.^[1][2][6]

Use the radon-preparation invalidation checklist

Before the start time, give every occupant one handoff note: exact device and room, start and stop times, required closed-house period, normal entry and exit, heating and cooling operation, active mitigation status, prohibited movement or interference, contact person, and what to record. For short tests under four days, EPA's current transaction guide calls for closed-house conditions at least 12 hours before and throughout the test; longer devices and state programs may differ.

Mark potential invalidation events instead of hiding them: open exterior window or door beyond normal entry, device moved or covered, power or active mitigation interruption, whole-house or window fan use, unusual high wind or severe storm for a short test, water intrusion, changed HVAC mode, incorrect duration, damaged seal, missing start or stop time, delayed laboratory return, or any departure from the kit and applicable protocol. Do not close combustion or makeup-air supplies to create test conditions.

When an event occurs, record time, duration, room, device status, weather, mitigation status, person, and action. Ask the qualified tester, laboratory or state radon program whether to extend, restart, or repeat; do not decide that a convenient result is valid. The checklist documents conditions, not code compliance or a guarantee that one measurement represents the annual average.^[1][2][6]

Close the test carefully and protect the record

At the instructed finish, record the actual stop time and complete the device’s sealing and return steps. EPA advises sending a completed lab-analyzed kit promptly. The package instructions control the acceptable shipment window and handling method. Keep a copy of the identifying information and submission details so you can match the eventual report to the correct room and exposure period.

Use a simple editorial filing system: one folder for instructions, placement photo, start and stop times, disturbance notes, return confirmation, and the final report. Assign one household member to check that the result arrives. A kit dropped in the mail is an unfinished decision until the report has been reviewed. If the laboratory rejects the sample, preserve its explanation and correct that specific preparation problem before repeating.^[1][4]

Give each household task an owner

The following is an editorial coordination example, not an additional testing standard. Put three names or initials on the calendar: the person preparing the house, the person recording the start, and the person ending and returning the test. They may all be you. Assigning the jobs makes it easier to spot a practical gap before the device is exposed, especially when work schedules, travel, or property access are involved.

Beside those names, add a short question list for the laboratory: which room fits this purpose, which ventilation controls need discussion, how quickly must the sample arrive, and what should we report if conditions change? Keep the answers with the instruction sheet. This approach avoids passing an incomplete verbal message between household members. It also leaves a clear place to record an unresolved question rather than quietly replacing the laboratory’s directions with a remembered internet tip.^[4]

Plan the follow-up before the number arrives

A short-term screening result is not an annual exposure measurement. CDC distinguishes short tests from tests lasting more than 90 days, which better represent longer-term conditions. Follow the applicable guidance for confirmation rather than declaring the home safe or unsafe from an isolated display reading. Keep units, test duration, and any laboratory qualifications attached to the number.

EPA recommends fixing homes at 4 pCi/L or above and considering reduction between 2 and 4 pCi/L; it does not describe lower results as risk-free. Initial short-test follow-up is part of the decision pathway. For elevated results, a disputed or interrupted test, unusual building layouts, or a time-sensitive transaction, contact the state radon program or a qualified measurement professional. Ask about required qualifications locally rather than assuming a generic certificate answers every jurisdiction’s requirements.^[3][5][4]