The EPA conducted a survey of oil and gas production wells hydraulically fractured by nine oil and gas service companies in the United States during 2009 and 2010. The objective of this report was to describe, for these wells: (1) well design and construction characteristics of hydraulically fractured oil and gas production wells, (2) the relationship of well design and construction characteristics to drinking water resources, and (3) the number and relative location of well construction barriers (i.e., casing and cement) that can prevent subsurface fluid movement.