Water supply safety assessment considering the water supply system resilience

The paper assumes that the measure of the loss of safety in water distribution is the risk related to the occurrence of some undesired events such as the failure to meet certain (required) water qual-ity conditions (that may have negative impacts on the consumer health), or a severe disruption of the water supply services. In this aspect, risk is assessed using the expected value of losses (haz-ardous effects) that may occur as a result of the occurrence of the undesirable events. A comparison of the determined values with the risk acceptability criteria is the basis for the safety assessment. The analysis was made based on the available operational data of the water supply subsystem. The analysis covered the period from 2011 to the third quarter of 2021 and was prepared on the basis of available physicochemical and microbiological analyses of water performed at the water and microbiology laboratory of the considered water supply system in Poland's Subcarpathian Province. A novel approach to risk analysis of the loss of safety in water supply system taking into account the occurrence of some undesired events was achieved. The estimated value of the risk level, under the given operating conditions, indicates that there is no real threat to water consumers.