A filter trap into which waste water can be dumped to separate particulate matter from the water. A sensor senses when the liquid level in the filter trap rises above a predetermined level, and triggers an alarm to indicate the filter basket is full of particulate matter and must be removed to dispose of the contents. The withdrawal of the filter basket from the filter trap causes the inlet thereto to automatically close so that waste water cannot be dumped into the filter trap when the filter basket has been removed. A sensor senses when the filter basket has been removed to provide a visual indication thereof.