This document discusses produced water, which is water brought to the surface during oil and gas production. It defines produced water and its characteristics, such as high salinity. It provides data on produced water volumes in the US and internationally, and the different management practices used. Finally, it outlines how the water needs and volumes produced vary between different types of hydrocarbon production such as conventional, coalbed methane, shale gas, and oil sands. While shale gas receives significant attention, it accounts for less than 6% of total produced water in the US.