Objective To construct a public health risk assessment index system for sudden water pollution incidents to provide a reference tool for conducting public health risk assessments of such incidents.

Methods An initial index list was established through literature review and group discussions. A two-round Delphi expert consultation method was employed to evaluate and screen the indicators, and a comprehensive integration empowerment method was used to calculate indicator weights.

Results The expert positive coefficients for the two rounds of consultation were 83.33% and 100.00%, respectively, and the authority coefficients were (0.79 ± 0.11) and (0.82 ± 0.08), respectively. The overall Kendall′s W values were 0.250 and 0.460 (both P < 0.001). Finally, 4 first-level indicators, 17 second-level indicators, and 66 third-level indicators were established. The top three third-level indicators by weight were the speed of emergency resource allocation (0.049 9), regular monitoring of drinking water quality by the jurisdictional water quality supervision department with monitoring items covering the conventional indicators listed in GB 5749 - 2022 (0.044 4), and the professional and technical level of emergency personnel (0.039 1).

Conclusions The constructed public health risk assessment index system for sudden water pollution incidents provides a reference for the health emergency response to water pollution incidents.