A grease trap for separating waste from waste water that includes grey water and FOG includes a tank having a bottom and an interior volume. An inlet invert in the tank has a discharge end for discharging waste water into the tank, and an outlet invert in the tank has a drain end for removing grey water from the tank. A first baffle across the interior volume below the discharge of the inlet invert and above the drain end of the outlet invert has a hole allowing grey water to descend through the hole to a path under the first baffle to the drain end of the outlet invert. A second baffle across the interior volume above the discharge of the inlet invert has a hole allowing FOG to float through the hole in the second baffle to collect above the second baffle.