The most prevalent of the radon isotopes in ground water is radon-222. This isotope presents the greatest health risk compared to the other naturally occurring radon isotopes if ingested via the water pathway.

1.1 This test method covers the measurement of radon in drinking water in concentrations above 0.04 Bq/L.

1.2 This test method may be used for absolute measurements by calibrating with a radium-226 standard or for relative measurements by comparing the measurements made with each other.

1.3 This standard does not purport to address the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.