A lavatory system within an internal cabin of a vehicle includes an enclosure defining an interior chamber, a first lavatory unit within the interior chamber, and a second lavatory within the interior chamber. The first lavatory unit is adjacent to the second lavatory unit. In at least one embodiment, a lavatory within an internal cabin of a vehicle includes an interior chamber defined by one or more outer walls, and a storage compartment extending outwardly from at least one of outer walls. The storage compartment defines an internal storage space that connects to the interior chamber. In at least one embodiment, a lavatory includes a first lavatory unit, a second lavatory adjacent to the first lavatory unit, and a containment compartment common to the first lavatory unit and the second lavatory unit.