Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes. Remove bacon from pan, keeping the drippings in the skillet. Allow bacon to cool; crumble and return to bacon drippings.
Stir flour into bacon and drippings over medium-high heat; cook and stir until flour is blended and lightly browned, 3 to 5 minutes. Slowly whisk water into flour mixture until thickened, about 5 minutes; season with salt and black pepper. Stir in tomatoes and simmer until gravy is cooked through, about 5 minutes. Serve over warmed biscuits.