Brown the sausage in a large skillet and do not drain the grease.
Sprinkle the flour on the sausage and cook on low-medium heat, stirring, for 3 minutes.
Slowly pour in the water, stirring and scraping any brown bits from the bottom of the pan.
Bring the gravy to a simmer, and stir. Gravy will thicken as it comes to a simmer.
Slowly pour in the milk and bring to a simmer.
Gravy will thicken as it cools, thin with more milk or water as needed. Season with pepper.