At a refinery, water is used in cooling processes; as boiler feed-water to make steam; to clean tanks and cement pads; as fire and laboratory supply; and for drinking water and sanitary needs. Specific uses include water-blasting to remove deposits from piping and process unit vessels and testing of tanks to make sure they hold pressure before they are filled with oil, gasoline or a similar substance (e.g., known as hydrostatic testing).

Water that has been in contact with petroleum products is put through Sunoco's on-site wastewater treatment facilities, which is an intense treatment process that includes, but is not limited to, screening; oil/solids/water separation; biological treatment and clarification. Some water is recycled to the process while other water undergoes further treatment prior to discharge.