Customer-Driven Water Supply Systems: Synergizing System Reliability and Customer Satisfaction with Bowtie Analysis

Conventional interview surveys for assessing customer satisfaction require supplementary resources and yield a low response rate. Covering fewer customers who generally face service interruptions is another limitation that hinders the identification of the root causes of failure. The survey findings might mislead the utilities by showing unrealistic satisfaction levels. Customer dissatisfaction risk subjects to the time between the complaint registration and the utility response pending full resolution of the issue. In the present research, bowtie analysis (BTA) reveals an innovative synergetic correlation between system reliability and customer satisfaction with water utilities. Using complaints reported due to service failures, the fault tree analysis (FTA) assesses the reliability of system components (pressure, water quality, and structure). On the opposite side of the bowtie, event tree analysis (ETA) evaluates the efficiency of the utility response and translates it into customer dissatisfaction risk. Exploring over 1500 registered work orders in a utility operating in British Columbia (Canada) reveals that 80% of complaints originated from structural (primarily service connections) issues. Simulating the BTA for five improvements showed that economical proactive maintenance and an efficient complaint response mechanism improve the system reliability from 58 to 86% and reduce the cumulative risk by 62%. The remaining risk reduction requires expensive improvements, e.g., source change and conventional treatment installation, which require customer approval based on willingness to pay. The study reveals that a complete bowtie analysis effectively integrates both the FTA and ETA and provides a novel customer-driven decision-support tool for water supply systems and other elsewhere applicable.