Objective To investigate the influencing factors for the qualified rate of water quality of centralized drinking water supply in the rural areas of Lu'an, China from 2015 to 2019, and to provide a data basis for relevant departments in improving strategies to guarantee drinking water safety.

Methods According to the requirements of the monitoring program, the water quality of centralized water supply in the rural areas of Lu'an was monitored during wet and dry seasons every year. The monitoring results were evaluated according to the Standards for Drinking Water Quality (GB 5749-2006). Chi-square test was used to compare the qualified rates of water samples. A logistic regression analysis was used to find the influencing factors for water quality.

Results During the five years, 3 016 water samples were monitored, and the overall qualified rate of water samples was 70.92% (2139 qualified samples). From 2015 to 2019, the qualified rate of water samples was 66.97%, 66.23%, 60.10%, 72.63%, and 87.15%, respectively. Indices with a low qualified rate were total coliform group, total colony count, and turbidity, which had a qualified rate of 78.38%, 94.03%, and 94.46%, respectively, and the qualified rates of other indices were more than 99%. A multivariate analysis showed that types of water sources, disinfection method, and size of water plants were the influencing factors for the qualified rates of water samples of centralized drinking water supply in the rural areas of Lu'an.

Conclusion The qualified rates of water samples of centralized drinking water supply in the rural areas of Lu'an showed a rising trend. Microbial indices were still the main influencing factors for water samples qualified rates. Therefore, targeted measures should be taken to ensure the safety of drinking water for rural residents.