This document specifies a method by liquid scintillation counting for the determination of tritium activity concentration in samples of marine waters, surface waters, ground waters, rain waters, drinking waters or of tritiated water ([³H]H₂O) in effluents.

The method is not directly applicable to the analysis of organically bound tritium; its determination requires additional chemical processing of the sample (such as chemical oxidation or combustion).

With suitable technical conditions, the detection limit may be as low as 1 Bq·l⁻¹. Tritium activity concentrations below 10⁶ Bq·l⁻¹ can be determined without any sample dilution.