What are the UK Action and Target Levels?
UKHSA's domestic Action Level is 200 becquerels per cubic metre of air (Bq/m³), expressed as an annual average. The Target Level of 100 Bq/m³ is the intended outcome for remediation and protective measures.
UKradon advises action at or above the Action Level in its measurement guidance. Between the Target and Action Levels, reducing radon should be considered, especially where a smoker or ex-smoker lives in the home. These are public-health references, not a sharp boundary between risk and no risk.
Guidance checked 17 September 2026: UKradon Action and Target Levels; measurement guidance.
Who should consider testing?
Use official radon potential information and UKHSA guidance to decide whether to test a home. Radon Map Check cannot make that decision from a postcode alone. Basements, cellars and underground sites require particular consideration regardless of the map location.
The usual domestic measurement approach uses two detectors, typically in a living area and occupied bedroom, over three months. Follow the provider's placement and return instructions.
Sources: UKradon map limitations; measuring radon.
What should homebuyers and landlords do?
Homebuyers should distinguish an address report from a measurement report. Ask what evidence is available and seek advice from the professional handling the transaction. UKradon's house-sales guidance explains the radon-related steps.
Landlords should consult current official sector guidance and obtain advice appropriate to the building and jurisdiction. This educational guide is not a legal compliance assessment and does not certify a property.
What happens after an elevated result?
- Read the test provider's report, including units and any uncertainty.
- Seek advice from a suitably experienced radon professional.
- Agree a building-specific approach rather than choosing solely from the map.
- Arrange a follow-up measurement to assess the work.
Radon Map Check's remediation guide outlines questions to ask. The detector guide explains testing options.
A measured result needs context
Short tests, room changes and building works can affect interpretation. Follow the laboratory's guidance. This site provides no diagnosis, personal risk estimate or safety certificate.