On June 4, 2015, the U.S. Environmental Protection Agency (EPA) released an external review draft of a report assessing the potential impacts of hydraulic fracturing on drinking water. The report, “Assessment of the Potential Impacts of Hydraulic Fracturing for Oil and Gas on Drinking Water Resources,” is the government’s most comprehensive investigation to date of the connection between drinking water and hydraulic fracturing. Overall, EPA did not find any evidence that current hydraulic fracturing mechanisms have had widespread, systemic impacts on drinking water resources. However, EPA did identify several potential vulnerabilities in the hydraulic fracturing process that could lead to future impacts.

The report was four years in the making, conducted based on EPA’s “Plan to Study the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources,” released in 2011. The report reviews over 950 sources, including scientific datasets and peer-reviewed literature. Currently, the report is only in draft form and is under review by EPA’s Science Advisory Board before being finalized. The draft is also open to public comment until August 28, 2015.

The report assesses potential drinking water impacts in five stages of the hydraulic fracturing cycle: water acquisition, chemical mixing, well injection, flowback and produced water, and wastewater treatment and waste disposal. EPA concluded that during each stage of the process, hydraulic fracturing could have adverse effects on drinking water depending on geographical factors and the potential for discharge or spills. For example, concerns exist where a relatively high amount of hydraulic fracturing is done in areas of drought or limited water resources. Additionally, EPA noted that discharges and spills, insufficient containment, and inadequate treatment of water from hydraulic fracturing sites could result in contamination of both aboveground and belowground drinking water.

However, on balance, EPA concluded that at present, hydraulic fracturing mechanisms have not caused any extensive effects on drinking water resources. Indeed, the data shows that over the years, hydraulic fracturing has been safely done under responsible regulatory programming. EPA noted that the number of identified cases where hydraulic fracturing impacted drinking water was very small compared to the number of hydraulic fracturing wells in operation. However, EPA acknowledged that its conclusion may be limited by insufficient data about hydraulic fracturing’s effects on groundwater.

The report’s findings are an interesting addition to the evolving conversation about hydraulic fracturing. In EPA’s press release, Dr. Thomas Burke, EPA’s science advisor and deputy assistant administrator of the Office of Research and Development, called the study “critical” to identifying “how best to protect public health and … drinking water resources.”

An executive summary and full text of the report can be downloaded here.