I do not propose to make radon testing in existing or new dwellings mandatory. My Department is not aware of any precedent for mandatory testing in other member states.
Under part C of the national building regulations, dwellings, including new local authority dwellings, commencing construction on or after 1 July 1998 must incorporate radon reduction measures. In high radon areas, where more than 10% of existing houses exceed the national reference level of 200 becquerels per cubic metre, foundations must incorporate radon proof membrane and a standby radon extraction sump. In other areas foundations must incorporate a standby radon extraction sump.
Later this year my Department will publish enhanced technical guidelines on compliance with the radon reduction requirements in the building code.