This interactive map shows sampling locations for water chemistry in rivers, wells, and drainage ditches in response to the Gold King mine spill. The objective of this data compilation: to assist responding agencies in coordinating, collaborating, and communicating who is sampling, where they are sampling, and when samples are being taken. Sample locations are linked back to each agency’s database or data repository.

The map is intended to help avoid duplication of effort, identify gaps in sample coverage, and provide a single reference that catalogues the locations of all sampling efforts with links for data discovery and access.

The map is not intended to either integrate or interpret the results of the data analyses from all the different data providers. Different data providers may use different procedures and sampling protocols, or sample for different materials, sample dissolved versus total solids, or use different standards in reporting results.

We are starting with sample analyses for arsenic, cadmium, lead and mercury in surface water over time. According to EPA, these four metals are the primary contaminants of concern due to their potential to pose significant health risks. We plan to post additional sample results to show the concentrations of all 24 metals in surface water as well as sediment sample results, during the coming weeks.


On 5 August 2015, approximately 3 million gallons of mineral-laden waters spilled from the Gold King mine into Cement Creek in Colorado. The discharged waters flowed downstream into the Animas River, and from there to the San Juan River in New Mexico before entering into Lake Powell in Utah and Arizona.

This map displays the locations of water samples collected by governmental organizations following the spill from the Gold King Mine.

The following organizations are sampling water. As sample sites are identified or new water chemistry data released, they will be posted on this map. Water chemistry results are maintained by each agency. Click on the individual map symbol for additional information, including a link to the data source.

Sampling Authorities


The sampling sites on this map are taken from information supplied by the organizations doing the sampling. Some sampling locations are approximate. The response to the spill is ongoing and new sampling sites are added as they are reported. In some cases, sampling organizations can share the locations of sampling sites even though the test results are pending or being reviewed and thus not publicly available yet.