Best practical technology (BPT) refers to any of the categories of technology-based effluent limitations pursuant to Section 301(b) and Sections 304(b) of the Clean Water Act as amended. These categories are the best practicable control technology currently available (BPT); the best available control technology (BAT) economically feasible (BAT); and the best conventional pollutant control technology (BCT).

Section 301(b) of the Clean Water Act specifies that "in order to carry out the objective of this Act there shall be achieved—(1)(A) not later than July 1, 1977, effluent limitations for point sources, other than publicly owned treatment works (i) which shall require the application of the best practicable control technology currently available as defined by the Administrator pursuant to Section 304(b) of this Act, or (ii) in the case of discharge into a publicly owned treatment works which meets the requirements of subparagraph (B) of this paragraph...