An oil water separator is a piece of underground equipment used to separate oil and water mixtures into their separate compartments (or chambers) further separated by baffles. There are many different types of oil-water separators and they can be designed to treat a variety of contaminants in water including free floating oil, emulsified oil, dissolved oil, and suspended solids. Each has different oil separation capability and are used in different industries. Oil water separators are designed and selected after consideration of oil separation performance parameters and life cycle cost considerations. Oil/water separators (OWS) are usually the first stage of a treatment system. However, in some cases, an oil water separator can also be used as an effective and necessary component of a facility's final treatment before discharge as well. An OWS can be used as an effective spill countermeasure to avoid the need for an emergency response for an illegal discharge. In cases where sudden releases may occur or a large steady discharge of petroleum impacted water or sediment is present, a properly maintained OWS is capable of handling sudden and large spills at elevated flow rates. The device separates oil-based liquid from any rain, process or wash water, thus discharging clean water and resulting in the reclamation of otherwise lost oil that can now be recycled. Oil water separators (OWS) are effective, but they do require periodic maintenance to perform as designed.