The EcoStop is an inlet-controlled spill protection device that detects oil leaks and shuts down water flows before oil can be discharged off site. The EcoStop valve is typically installed in a below-grade catch basin downstream of catchment areas determined to be at high risk for oil spills like fueling pads, generator storage areas, parking lots, industrial yards, and more. In standard operation, the EcoStop valve floats on the surface of the water and water freely exits the structure. In the event of an oil spill, oil builds up in the discharge catch basin and the EcoStop float begins to sink in response to the level of the water and oil interface. Once the oil reaches a specific level, an actuated closure device causes the float to sink and seals off the influent pipe watertight up to 16 feet of total dynamic head pressure.