Cluster of Wells

Green pin signifying a well that is in compliance or has no water contaminant exceedences

Well In Compliance

Red pin signifying a well that is in not compliance or has water contaminant exceedences

Well Not In Compliance



Tracking groundwater contamination at coal combustion waste disposal sites.

Environmental Integrity Project developed Ashtracker to help people access detailed information about groundwater contamination near areas used to dispose of ash, scrubber sludge or other wastes from coal burning power plants. The map allows viewers to locate monitoring wells at these sites and review data on specific concentrations of pollutants such as arsenic, selenium and lead that have accumulated in groundwater above federal health advisory levels. See the glossary for more information on these standards.

Navigate to site profiles by clicking on blue map markers or the links listed under "Facility Data". The profile view includes details about site locations and ownership, along with a pollutant table that indicates the monitoring status of each contaminant. Scroll down for a site description and also for a link where you can download raw groundwater monitoring data.

Clicking one of the red or green wells brings up a close-up view of where the monitoring well is located. Wells colored red are locations where arsenic, boron, manganese or other pollutants have been measured in concentrations that exceed federal standards that protect public health. A panel on the left-hand side identifies the specific pollutants that have exceeded these levels, and includes links that provide access to more detailed data about all pollutants measured at the site.

At red wells, pollutants that exceeded federal health-based standards at the site are identified in red. Clicking on one of the pollutants in red brings up summaries for any exceedance of the federal standards at that well location. See the "About" page for more information on how are data are obtained, and its limitations.

Data Summary

This application displays data from 39,080 groundwater quality readings collected at 1,010 monitoring wells. Of these measurements, 4,731 (12%) exceeded U.S. Environmental Protection Agency thresholds for safe drinking water. In the last four years, 828 (82%) of currently listed groundwater wells exceeded federal safe drinking water thresholds for one or more pollutants.

The five most prevalent contaminants (see below) accounted for 80% of all exceedances.

Total Facilities Online


Total Wells Online

Most Common Exceedances
SO4 Sulfate
640 wells
Mn Manganese
218 wells
B Boron
215 wells
As Arsenic
113 wells
Co Cobalt
78 wells