FOG stands for fats, oils, and grease, which are typically found in kitchen settings, as lard, oil, butter, salad dressing, peanut butter, gravy, and more. When cleaning up a meal, it’s not uncommon to rinse plates and utensils of these kinds of remnants that can slip down the drain but never fully break down. Using soap and hot water may appear to get rid of it, but when cooled, it will actually collect and reform farther down the pipes, even if the sink has a garbage disposal connected to a grease trap. Once down the drain, it doesn’t seem like an issue anymore, but that’s actually where the problems begin.