Regulations are not laws. They are the specific implementation mechanisms of laws.
For example, Congress passes a law like the Clean Water Act. But that law doesn't (and cannot feasibily) lay out every single individual rule necessary to ensure the clean water that it seeks to protect and provide.
For example, it contains a section that requires Water Quality Standards to be set by each state, for themselves. However, if a state does not create them, the act authorizes the EPA to create a standard for them.
That's not the EPA "creating laws", it's the EPA implementing the congressionally-passed CWA.