Tight oil is a type of light, unconventional crude oil found within low permeability reservoir rocks like sandstone and limestone. New horizontal drilling and multi-stage hydraulic fracturing technologies allow this previously uneconomical resource to be produced. The United States currently has significant tight oil reserves and production. Tight oil has the potential to greatly increase global oil reserves and offset declines in conventional production. However, production comes with environmental risks like potential groundwater contamination and large water usage that require mitigation efforts.