Abstract: This invention relates to a facility for storage of liquids, and more specifically, a leak detection system for an automotive service station. This system consists of a plurality of tanks provided with pipelines. This tank system is stored in a multi-walled vault or containment box. The pump lines are surrounded or contained with return spill casings. If a leak occurs in the lines, the gasoline flows by gravity to a separate service chamber. In this rectangular service chamber, the leak can be visibly observed from a top view by a service station attendant and should a pipeline require replacement, it is readily withdrawn from its casing and replaced, without any excavation.