Laws and regulations are different, and it is extremely important to appreciate the difference while addressing an environmental issue. Often, one has to check both the applicable law(s) and the regulations.

Environmental Laws are passed by our elected representatives. Thus, for example, the US Congress passed the Clean Water Act to help clean up, and keep clean, our water bodies (rivers, streams, lakes, and other surface waters, primarily). Within such laws are stipulations about how they are to be implemented, through regulations developed by state or federal regulatory agencies, such as the Environmental Protection Agency.

Here is a list of laws EPA administers. The regulations that EPA has developed are in Title 40 of the Code of Federal Regulations, which can be found here. States have analogous sites for their laws and regulations.