Under the Clean Water Act (CWA), point source dischargers are required to obtain federal discharge permits and to comply with permit limits sufficient to make progress toward the achievement of water quality standards or goals. As water quality standards become increasingly stringent, industrial and municipal dischargers are being pressured to accept permit limits that are difficult, if not impossible, to meet. Since a discharge permit is equivalent to a contract between the discharger and the regulatory agency, permit holders must be increasingly wary of the contract terms and must carefully evaluate the effluent limitations agreed to in discharge permits. Such caution is especially warranted in light of the "antibacksliding" provisions contained in the CWA. Unknowingly, dischargers may be agreeing to permit limits that are not reasonably attainable yet may not be relaxed.

The CWA provides that the discharge of any pollutant into the waters of the United States by any person is unlawful except when these discharges are subject to a national pollutant discharge elimination system (NPDES) permit or some other statutory exception. In order to make strides toward achieving the Act's goal of eliminating the discharge of all pollutants, point source dischargers are issued NPDES permits that contain conditions whereby publicly owned treatment works (POTWs) and industrial dischargers must meet minimum technology-based requirements. The applicable treatment technologies for these dischargers are secondary treatment and best available technology (BAT), respectively.