The intended use of an oil/water separator(s) (OWS) determines whether the separator is subject to the SPCC regulations and, if so, what provisions are applicable. explains the applicability of the SPCC rule to OWS, and clarifies the exemption for certain uses, including equipment, vessels, and containers that are not specifically called “OWS” but perform oil/water separation, such as water clarifiers at wastewater treatment plants. This section also discusses the alternative compliance options for flow-through process vessels at oil production facilities.

The table below outlines the SPCC rule applicability for various uses of OWS. Only OWS used exclusively to treat wastewater and not used to satisfy any requirement of 40 CFR part 112 are exempt from all SPCC requirements. OWS used in oil production, recovery or recycling and to meet the secondary containment requirements of the rule are not exempt.