How to Test for Radon in Your Home

Radon is the second leading cause of lung cancer in the UK, responsible for around 1,100 deaths per year. It is a colourless, odourless gas — you cannot detect it without a test. Testing is the only way to know your home's radon level, and it is straightforward, inexpensive, and takes about 90 days.

Step-by-Step Guide to Testing for Radon

  1. 1

    Check your area risk

    Use your postcode district to look up local radon risk levels on the BGS indicative map. High-risk areas should prioritise testing. Enter your postcode below to check instantly.

  2. 2

    Order a radon test kit

    Purchase an accredited radon detector from UK Radon — accredited testing service or similar. Long-term detectors (90 days) give the most accurate results. Kits typically cost around £29.

  3. 3

    Place the detector correctly

    Put one detector in the main living area (ground floor) and one in the bedroom. Follow the included instructions — keep detectors away from draughts, direct sunlight, and external walls. Do not place them in kitchens, bathrooms, or utility rooms.

  4. 4

    Return the detector after 90 days

    Send the detector back to the laboratory in the prepaid envelope provided. Avoid testing during summer — winter or spring/autumn testing gives more representative annual results, as radon levels are typically higher when windows are kept closed.

  5. 5

    Review your results

    The laboratory sends a report with your radon concentration measured in Becquerels per cubic metre (Bq/m³). The UK Action Level is 200 Bq/m³. Above that, UKHSA recommends taking remediation steps to reduce radon levels in your home.

Which Test Kit Should You Buy?

There are two main types of radon detector available in the UK:

Long-term detector (90 days) — Recommended

Measures radon over 3 months, giving an average that accounts for day-to-day variation. This is the standard approach recommended by UKHSA and BGS. Results are more reliable and suitable for making decisions about remediation. Cost: ~£29.

Short-term detector (7 days) — Less accurate

Gives a faster result but radon levels fluctuate significantly day to day. Short-term tests are less representative of your actual annual exposure and are not recommended for making remediation decisions. Use only for a quick initial check.

For accredited postal test kits, visit UK Radon — accredited testing service .

What Does the Result Mean?

Your result is expressed in Becquerels per cubic metre (Bq/m³). Use the table below to understand what your reading means and what action to take.

Radon test result interpretation guide
Result Action
Below 100 Bq/m³ Low — no action needed
100–199 Bq/m³ Moderate — consider testing again in a year
200 Bq/m³ or above At or above the Action Level — take remediation steps
1000 Bq/m³ or above High — take action promptly; seek professional assessment

Check Your Area First

Enter your postcode district to see local radon risk levels before ordering a test kit.

Guidance based on UKHSA and BGS recommendations.