# The Water Supply (Water Quality) Regulations 2018, Paragraph 2: Screening for certain radionuclides, or screening for an individual radionuclide


(1) If one of the activity concentrations exceeds 20% of the corresponding derived value or the tritium concentration exceeds its parametric value listed in Schedule 2 an analysis of additional radionuclides is required.
(2) In deciding which radionuclides are required to be measured for each supply, a water undertaker must take into account all relevant information about likely sources of radioactivity.

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Source: https://www.legislation.gov.uk/wsi/2018/647/schedule/4/paragraph/2 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-2018/schedule-4/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.