The city consumed vast amounts of water, due to the fact that nearly every house was connected to a sewer, had a bathroom (Figure 2), and had a water-flushed latrine (Webster, 1962). For instance, the Mohenjo-Daro “was serviced by at least 700 wells, with an average frequency of one in every third house… [and the] cylindrical well shafts were constructed using wedge-shaped bricks” (Mays, 2010). Much of the water people used passed through a “network of effluent drains [Figure 3] (built of brick masonry) constructed along the streets. These drains, located along one side of the street, were U-shaped approximately 50–60 cm deep…[and] built of bricks set in clay mortar with covers made of loose bricks, flagstones or wooden boards [which] could be removed for cleaning purposes” (Mays 2010). The contents of the drains were diverted either to some public drain or to a catchment basin (Mays, 2010), but they first went through terracotta pipes into “…a tightly built terracotta or brick sump or cesspool in which the solid matter was deposited” (Figure 4)(Webster, 1962). The drain holes were built of brick and precisely fitted so that “even today the joints are hardly visible” (Webster, 1962). If the latrines or bathrooms were not on the ground floor, the spillways “…were stepped so that the water pouring down would not splash the passerby in the street” (Webster, 1962).

Figure 2: “Paved bathroom with outlet through the wall on the left” (Webster, 1962)

Photo Source: Webster 1962

Figure 3: “Sewer outlet from house” (Webster, 1962)

Photo Source: Webster, 1962

Figure 4: “Brick-lined sump located at the end of a street” (Webster, 1962)

Photo Source: Webster 1962

One of the most famous of the hydraulic feats of Mohenjo-Daro is its Great Bath (Figure 5). “The Great Bath of Mohenjo-Daro measured 52 m north-south by 32.4 m east-west with an area of 1,700 m^2. The center piece of the Great Bath was the pool, a sunken rectangular basin approximately 12 × 7 m and 2.4 m deep” (Mays 2010). The bath has an inner lining of burned brick, followed by a layer of bitumen, and then puddled clay between two brick walls, in order to prevent water-logging (Webster, 1962). “The water from the bath flowed through a square hole in one corner into a passage with a flat soffit supported by wooden beams. A vertical manhole at one end provided for inspection and cleaning. The water passed out to a culvert [of] about 2ft 4 in” (Webster, 1962). It is unclear whether the culvert or a well was used to fill the bath (Webster, 1962).

Figure 5: Great Bath of Mohenjo-Daro

Photo Source: Mughal 2011

“Even today in most of Pakistan and India the same model of drainage is followed [that] was used in Mohenjo-daro. This indicates the advanced engineering and uban planning of the Indus Valley civilization” (Mughal, 2011).