Objectives In order to ensure the safety of centralized water supply, to effectively control water-borne infectious diseases, endemic diseases, tumors and any outbreaks of other water-borne diseases, and to provide technical support for the second waterworks in Lianshui County, the potential risks for source water were identified, analyzed and evaluated.

Methods Hygienic status of water source and the prevalence of water-borne diseases on the site of the project were investigated. The quality of source water samples both in dry and wet seasons were collected and analyzed, relevant information were sorted and evaluated. Based on the Environment Quality Standards for Surface Water (GB 3838-2002), a WQI index.Method was used to make a comprehensive assessment and grade the quality of source water to demonstrate the feasibility of the project.

Results Based on the on-site investigation, water samples from areas, covering farm, forestry, animal husbandry and fishery, together with the influence of transportation, routine life of people and scientifically managed iatrogenic pollution around 10-kilometers upstream and 5-kilometers downstream of the water source, were collected and proved that no harmful effect on water quality. The quality of source water from the water intake was good generally, except fecal coliform bacteria and iron; the result of other indicators were in class Ⅰ or class Ⅱ, which meant that the source water in this site was qualified and basically met the requirement of hygienic standards and could be used as drinking water.

Conclusions The project which designed to construct a water intake in this site as the source of urban drinking water was reasonable and feasible.