Which item is not typically considered part of the secondary containment system?

• A. Under Dispenser Containment
• B. Double Wall Piping
• C. Monitoring Well
• D. Containment Sensor

Answer: (C)

Secondary containment combines physical barriers and monitoring that prevent and detect leaks from storage tanks. The items that form the containment boundary include under dispenser containment, which catches spills around the dispenser; double wall piping, which keeps contents within the piping and provides an inner barrier; and containment sensors that monitor the integrity and alert when a leak occurs within the containment system. A monitoring well, however, sits outside the containment boundary and is used to sample groundwater to detect whether contaminants have escaped the system. It supports environmental monitoring, not the physical containment itself, so it’s not typically considered part of the secondary containment system.