The Clean Water Act was initially passed in which year?

The Clean Water Act was originally passed in 1972, marking a significant milestone in U.S. environmental legislation. This legislation was established to regulate the discharge of pollutants into the waters of the United States and to ensure the quality of surface waters. The Act aimed to restore and maintain the integrity of the nation's waters by setting water quality standards and regulating pollutant discharges, thus greatly enhancing efforts to mitigate water pollution.

The passage of the Clean Water Act represented a response to growing concerns over water pollution that had become apparent in the 1960s, particularly highlighted by events such as the heavily polluted Cuyahoga River catching fire in 1969. The 1972 Act established a framework for the federal-state partnership to tackle water pollution while also setting in motion the creation of the Environmental Protection Agency (EPA), which was tasked with the enforcement and oversight of these regulations.

The other years mentioned do not correspond to the initial passage of the Clean Water Act. The early 1980s and mid-1980s are too late compared to the original legislation. While there have been subsequent amendments and changes to the Act since its initial passage in 1972, the foundation of the Clean Water Act was firmly established during that year.