# The Water Supply (Water Quality) Regulations (Northern Ireland) 2017, Paragraph 1


A water undertaker may use a screening strategy for gross alpha and gross beta to monitor for the parametric indicator value for indicative dose . The recommended screening value for gross alpha is 0.1Bq/l and for gross beta is 1.0Bq/l.
If the gross alpha activity exceeds 0.1Bq/l or the gross beta activity exceeds 1.0Bq/l, analysis for specific radionuclides is required.
The radionuclides to be measured must be based on all relevant information about likely sources of radioactivity.

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Source: https://www.legislation.gov.uk/nisr/2017/212/schedule/5/paragraph/1 (the official version)
Page: https://openlegislation.uk/water-supply-water-quality-regulations-northern-ireland-2017/schedule-5/paragraph-1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.