The tank would have been open to the sky, but the surrounding structures would have been roofed. The sidewalls and parts of the floor have been conserved using modern replica bricks.
The Great Bath at Mohenjo-daro related images.
At the southwestern corner of the sloping floor, a small drain first passes through the massive walls of the tank and connects to a corbelled arch drain that curves along the edge of the northern terrace of the granary to the west.
The floor slopes down to the southwest corner where a small outlet (top right) leads to a brick drain, which takes the water to the edge of the mound.
This drain cuts through the edge of the so-called granary. If the entire drain were constructed along with the Great Bath, this feature would indicate that the original "granary" was built before the great bath.