Aqua Vault Storm/Sanitary Structures dispose of sewage to different destinations according to the type. Both storm and sanitary structures are necessary parts of the piping system. But, there’s a difference between how they work. A storm sewer carries rainfall runoff and leaves into rivers, streams and other bodies of water. In contrast, sanitary structures are underground pipes that carry sewage from kitchens and bathrooms to wastewater treatment plants where they are filtered, treated, and discharged.