Groundwater Threats in California

This layer shows the sum of weighted sites containing hazardous substances that pose a threat to groundwater in California at the census tract level. Since the nature and the magnitude of the threat and burden posed by hazardous substances vary among the different types of sites as well as the site status, the indicator takes both into account. Weights were also adjusted based on proximity to populated census blocks. The data is from the California State Water Resources Control Board, obtained via the CalEnviroScreen 4.0 tool.