Skim fat from pan drippings, being careful not to lose any of the brown sediment. Discard fat; leave 1/4 cup pan drippings.
Pour pan drippings into a saucepan. Add flour, stirring until smooth. Cook over low heat 2 minutes, stirring constantly. Add water; cook over medium-high heat 1 minute, stirring constantly, until thickened and bubbly. Stir in salt and pepper.