Trench drains which discharge water into bio-swells, storm drain systems and sewers are required to intercept and filter out hydrocarbons. Trench drains are often used to capture water from driveways, storage yards, distribution centers, parking lots and entry/exit ways of all types. Trench drains are the main areas where oil, diesel oil/fuel, oil sheen and hydrocarbons of many types originate. Trench drain filters should be widely used to capture hydrocarbon runoff. One 6 foot trench drain filter can prevent 50% of street oil from entering the storm drain system.