Gene Goforth sells showerheads—big ones, like the Raindance Imperial 600 AIR. Selling for as much as $5,457, it has a 24-inch spray face, 358 no-clog channels and a triple-massage option. "You can just stand under it, and it helps your psyche," says Mr. Goforth, who has one in his home.

Now, Mr. Goforth is in a lather over the federal government's...