Place flour in a medium bowl.
Combine water and roast chicken drippings in a liquid measuring cup. Pour 2 to 3 tablespoons into the flour and whisk until combined and thick, but not pasty.
Transfer both liquid and flour mixtures to a roasting pan set over a burner on the stove. Whisk to combine and turn heat to medium. Cook, stirring constantly, until gravy is thickened and bubbly. Season with salt and pepper.
