Indicators to describe a risk of violations of mandatory requirements in providing the population with safe and qualitative drinking water: methodical and practical aspects

Risk indicators of violation of mandatory requirements serve as grounds for unscheduled inspections. They are fixed in the Russian legislation and are a promising instrument of public administration. In surveillance over drinking water supply, a risk indicatoris represented by detection of a chemical in concentrations above the upper 95 % confidence limit of the average long-term level in two subsequent samples taken within monitoring of drinking water. The aim of this study was to develop a unified approach to calculating risk indicators of violations of mandatory requirements to drinking water supply and to estimate possibilities of their use in practice. The indicatoris considered an instrument foridentifying and preventing violations with the most adverse outcomes. The calculation algorithm and practical use of the indicator were tested using actual monitoring data collected in a specific region (more than 100 control points; 32 chemicals; 3 years of research). An association between detected violations of mandatory requirements and actual deterioration of drinking water quality was assessed using odds ratio (OR). An association was considered significant at OR > 1.0, when both upper and bottom limits of the confidence interval (CI) were above 1.0. The step-by-step algorithm for calculating the upper 95 % confidence limit of a pollutant concentration (the criterion value of the risk indicator) includes the following stages: verification and preparation of initial data; calculation of criterion values; creation a database with criterion values and its integration into the Rospotrebnadzor’s Unified Information System. A significant association was evidenced between some violations of mandatory requirements and deteriorating quality of drinking water. Thus, likelihood that safe standards for drinking water will be violated authentically increases due to violations of mandatory requirements to operative elimination of accidents or technical failures in water treatment: OR = 4.54 (CI: 1.98–10.43); violations of mandatory requirements to the first area in the sanitary protection zone around a waterintake, OR = 3.26 (CI: 1.54–6.88) etc. In 2025, unscheduled control and surveillance activities ‘triggered’ by the risk indicator were approved by regional public prosecutor’s offices and conducted in the Novosibirsk, Sverdlovsk, Tyumen region, Tatarstan, and some other regions. Violations of mandatory requirements were found in 22 out of 26 cases; reports of administrative infractions were issued concerning subjects under control; orders were issued to eliminate non-conformities. Implementing risk indicators of violations of mandatory requirements to surveillance practices seems an advisable process, whichis in line with key trends in development of the public administration system. A methodical document that unifies the procedure forindicator use and spread of the best available practices in the sphere will make it possible to extend use of the instrument and raise effectiveness of its application.