The Water Quality Viewer is a mapping and data visualization tool for exploring drinking water quality data for community water systems (CWS) in California. A CWS is a type of public water system that serves at least 15 service connections used by yearlong residents or regularly serves at least 25 yearlong residents within the system's service area. Each dot on the map represents a CWS. The color of each dot represents the annual average or maximum concentration of an individual contaminant for a given year.
The map and charts of the tool can be used to see how drinking water quality in California varies by location and over time for each contaminant:
- Level of contaminant in drinking water: These data show annual average concentrations and annual maximum concentrations of a contaminant in finished (treated) drinking water in micrograms per liter (µg/L).
- Distribution of level of contaminant in drinking water: These data show the number of community water systems and their concentrations of contaminants.
- Population potentially exposed to the drinking water: These data show estimates of the number of people served by community water systems by the concentration level of contaminants.
Suggested Citation
Please use the following citation when using mapping results in reports or other materials:
Tracking California, Public Health Institute. Drinking Water Quality Viewer. Accessed from www.trackingcalifornia.org/data-and-tools/water-quality [Date Accessed].