Development of a Web-Based Tool to Collect and Display Water System Customer Service Areas for Public Health Action

Significant illness is associated with biological contaminants in drinking water, but little is known about health effects from low levels of chemical contamination in drinking water. To examine these effects in epidemiological studies, the sources of drinking water of study populations need to be known. The California Environmental Health Tracking Program developed an online application that would collect data on the geographic location of public water system (PWS) customer service areas in California, which then could be linked to demographic and drinking water quality data. We deployed the Water Boundary Tool (WBT), a Web-based geospatial crowdsourcing application that can manage customer service boundary data for each PWS in California and can track changes over time. We also conducted a needs assessment for expansion to other states. The WBT was designed for water system operators, local and state regulatory agencies, and government entities. Since its public launch in 2012, the WBT has collected service area boundaries for about 2300 individual PWS, serving more than 90% of the California population. Results of the needs assessment suggest interest and utility for deploying such a tool among states lacking statewide PWS service area boundary data. Although the WBT data set is incomplete, it has already been used for a variety of applications, including fulfilling legislatively mandated reporting requirements and linking customer service areas to drinking water quality data to better understand local water quality issues. Development of this tool holds promise to assist with outbreak investigations and prevention, environmental health monitoring, and emergency preparedness and response.