This document describes a test method for the determination of radon-222 (²²²Rn) activity concentration in non-saline waters by extraction and liquid scintillation counting.

The ²²²Rn activity concentrations, which can be measured by this test method utilizing currently available instruments, are above？0,5？Bq·l^？1 which is the typical detection limit for a？10？ml test sample and a measuring time of？1？h.

It is the responsibility of the laboratory to ensure the validity of this test method for water samples of untested matrices.

Annex？A gives indication on the necessary counting conditions to meet the required detection limits for drinking water monitoring.