Objective To investigate the water quality and sanitary condition of integrated urban and rural water supply in Dezhou, Shandong province, China, and to provide a basis for the action of improving water sanitation.

Methods According to the Surveillance Program of Drinking Water Sanitation in Dezhou, the finished and terminal water from 16 integrated water plants in 11 counties/county-level cities/districts of Dezhou were monitored. From 2017 to 2019, all the 16 surveillance sites of finished water and 334 (in 2017)/324 (in 2018)/359 (in 2019) surveillance sites of terminal water were inspected for three consecutive years. The water from each surveillance site was sampled twice a year, once in dry season and once in wet season. According to the Standard Examination Methods for Drinking Water (GB/T 5750-2006) and Standards for Drinking Water Quality (GB 5749-2006), the water samples were examined and the results were determined.

Results A total of 2 130 water samples were examined from 2017 to 2019, of which 82.16% (1 750/2 130) reached the standards. Specifically, 99.48% (2 119/2 130) reached the microbiological standards, 95.31% (2 030/2 130) reached the toxicological standard, 83.15% (1 771/2 130) reached the sensory and general chemical standards, and 96.57% (2 057/2 130) reached the disinfection standards, and there were significant differences in the rates of reaching the last three standards among various years (χ²=12.781, 12.912, and 71.500, respectively, all P < 0.05).In terms of various years, the pass rates of water samples were 81.00% (567/700) in 2017, 78.97% (537/680) in 2018, and 86.13% (646/750) in 2019, with a significant difference among them (χ²=13.441, P < 0.01). In terms of different seasons, in 2017 to 2019, the overall pass rates of water samples were 84.60%(901/1 065) in dry season and 79.72%(849/1 065) in wet season, with a significant difference between the two seasons(χ²=8.661, P < 0.05). During the three years from 2017 to 2019, the indicators that had alway sexceeded the standards values included total number of bacterial colonies, sulfate, fluoride, aluminum and disinfectant residue.

Conclusion From 2017 to 2019, the water quality in rural and urban areas of Dezhou is stable in general. It is necessary to focus on controlling the total number of bacterial colonies, sulfate, fluoride, aluminum, and disinfectant residue in water.