My understanding is that community governments or individual utilities decide whether their water supplies are treated with fluoride, depending on whether the water provider is a public or private utility. The federal government, through EPA, just requires that the utilities provide their customers with an annual report about what's in their water. The state government decides whether those reports are forwarded to the federal level. You can check whether your utility puts fluoride in your water at this site from the federal Centers for Disease Control and Prevention: here. I can see that in my county, only 1 out of 69 utilities puts fluoride in their water.

Pesticides are sprayed by a lot of folks - federal, state, local, and private. Where I live, people got the local government to stop spraying public lands. Now the county transportation department uses goats to control some of the noxious weeds. None of that was federal.

And yes, it can get worse. It has been worse . If we had the same automobile emissions as we had in the 1960s, our air quality would be a lot worse. It takes a lot of effort to keep getting better.