GW Threat

Groundwater Threats

What are groundwater threats?

Hazardous chemicals are often stored in containers on land or in underground storage tanks. Leaks from these containers and tanks can contaminate soil and pollute groundwater.  Common pollutants of soil and groundwater include gasoline and diesel fuel from gas stations, as well as solvents, heavy metals and pesticides. The land and groundwater may take many years to clean up. Man-made ponds containing water produced from oil and gas activities may also contain pollutants.


Why is this indicator included in CalEnviroScreen?

  • Leaking tanks can expose people to contaminated soil and air.
  • People who live near contaminated groundwater may be exposed to chemicals moving from the soil into the air inside their homes.
  • Some cancer-causing chemicals from cleanup sites have been found in drinking water supplies in California.


How are groundwater threats measured in CalEnviroScreen 3.0?

  • The State Water Resources Control Board maintains a database of places where groundwater may be threatened by certain sources of pollution.
  • The scores for sites that threaten groundwater quality are added together for each census tract.
  • The score is based on information about the type of site and how close it is to neighborhoods where people live.
  • A complete description of the Groundwater Threats indicator can be found in the CalEnviroScreen 3.0 report.


Where can I find the more information about leaking underground storage tanks and threats to groundwater quality?

CalEnviroScreen 3.0 Groundwater Threats Map

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