We
evaluated the overall water footprint of hydraulic fracturing
of unconventional shale gas and oil throughout the United States based
on integrated data from multiple database sources. We show that between
2005 and 2014, unconventional shale gas and oil extraction used 708
billion liters and 232 billion liters of water, respectively. From
2012 to 2014, the annual water use rates were 116 billion liters per
year for shale gas and 66 billion liters per year for unconventional
oil. Integrated data from 6 to 10 years of operation yielded 803 billion
liters of combined flowback and produced water from unconventional
shale gas and oil formations. While the hydraulic fracturing revolution
has increased water use and wastewater production in the United States,
its water use and produced water intensity is lower than other energy
extraction methods and represents only a fraction of total industrial
water use nationwide