The Clean Water Act (CWA) of 1972 was a complete overhaul of the original Federal Water Pollution Control Act of 1948. That doesn’t tell much about it, except that water pollution has been a concern for a long time.
The 1972 CWA did a lot of stuff: established a structure for regulating point discharges (NPDES Permits); gave the EPA authority to implement programs and set standards; maintained existing requirements to set surface water quality standards; made it illegal for anyone to make a point discharge into navigable waterways without a permit; funded construction of sewage treatment facilities through grants; recognized the need to address nonpoint source pollution.
Over the past 50+ years there have been some changes to the CWA clarifying and revising it, but in essence, the 1972 Act hasn’t substantially changed.
So what it is, is the structure for regulating water pollution in the US, in particular in Waters of the US (WOTUS) or navigable waters. (That’s a whole different discussion.) Essentially it says “Thou shalt not pollute…without permission.”
So what does it do? That’s a lot harder to answer, because it is so big.
The purpose of the CWA is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” How it does that gets complicated. The EPA and the state level equivalents have created and enforce laws and permitting requirements. They also administer grants to help clean things up. They impose fines on bad actors.They provide education and awareness campaigns. And, when needed, they help with clean ups.
The CWA applies to both companies and municipalities that either directly or indirectly may introduce dredged or fill material into U.S. waters, with particular emphasis on municipal, agricultural, commercial, and industrial activities. These activities may include: generation and pretreatment of pollutants; wastewater management, stormwater runoff, dredging and filling, biosolids, concentrated animal feeding operations, and spill prevention and remediation.
Sources:
https://www.epa.gov/laws-regulations/history-clean-water-act
https://www.epa.gov/laws-regulations/summary-clean-water-act
https://www.justice.gov/enrd/water
https://www.jdsupra.com/legalnews/the-ultimate-guide-to-clean-water-act-2430596/
