No, the political appointees who run the EPA do change with a different administration. In the US system, the president (via appointees) runs the agencies.
Yes, the rulebooks are literally rewritten every 4-8 years. EPA examples, Trump renewed the permit for the Keystone XL pipeline (Obama had denied it), 'rewrote key rules curbing U.S. carbon emissions and other environmental regulations' (1), rolled back all of the Obama administration's fuel economy & emission standards, rolled back efficient lighting regulations, etc. He replaced the Clean Power Plan, redefined what species are endangered, weakened the Coal Ash rule, revised the Mercury standards. And so on.
He did all of these directly through the EPA- not by passing new laws. Then, Biden reversed all of these
1. https://en.wikipedia.org/wiki/Environmental_policy_of_the_Do...