Safe water corresponds to the percentage of water controlled and with good quality. It is calculated by the product of the compliance rate frequency sampling and the percentage of compliance with the parametric values of the parameters set by law subject, as defined in Annex II of Decree Law n.º 306/2007 of 27 August.

Percentage of analyzes performed = [1-(Number of analyzes missing)/ (Number of mandatory analyzes by regulation)]*100
Percentage of analyzes in compliance with parametric values = [(Number of analyzes in compliance with parametric values)/ (Number of analyzes performed with parametric values)]*100

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