The town proper lies to the east of the citadel. Streets running approximately north-south and east-west divided the large area into blocks of ca. 370m X 250m. Of perhaps twelve blocks, seven have been investigated by archaeologists. The citadel may, in fact, occupy one of the central blocks on the west side. Main streets could be as wide as 10m, while side streets were narrower, 1.5—3.0m in width. Although unpaved, the streets were provided with covered drains of baked brick. Manholes, covered, located at periodic intervals provided access into the drains. Clay pipes and chutes allowed waste material from private houses to reach the drains in the street. What happened to the refuse when it reached the edge of the city is not known.
Private houses appear comfortable. They vary in size, from single-room houses to mediumsized (court and one dozen rooms) to big (several courts, several dozen rooms). As in Mesopotamia, the house focused on a central courtyard. Rooms surrounded it, usually arranged on two stories. Baked brick was the standard building material for walls, an urban practice that contrasts with the air-dried mud brick typically used in towns and villages. House floors consisted either of beaten earth or brick, baked or air-dried. Roofing materials have not survived, but we may guess they consisted of lighter timber, reeds, and clay, as elsewhere in the Near East. Cuttings, sometimes square, indicate the use of precisely cut wooden beams; such beams spanned distances as great as 4m. Although mud plaster was occasionally used to coat internal wall surfaces, the walls were never decorated with paintings.
Houses usually had their own well. Indeed, 600 wells have been found at Mohenjo-Daro. Houses were furnished also with bathrooms, generally on the ground floor. The flooring of bathrooms was lining with finely sawn bricks or, in some cases, a plaster of brick dust and lime. Smaller rooms constructed in the same technique were identified as toilets.
Throughout the city, other buildings surely sheltered a variety of functions: residential, religious, or commercial. Of particular interest are the following. Some barrack-like groups of single-roomed tenements were found, possibly housing for the poor, or even for slaves. House A1, a building in the area labeled HR, may indeed be a prominent house, or it might be a temple. It stands out, with its monumental entrance and double stairway leading to a raised platform on which was discovered a rare stone sculpture of a seated figure. Other buildings with thick walls or unusual plan have also been tentatively interpreted as temples, but the evidence is nowhere compelling. Shops existed throughout the lower town; potters’ kilns, dyers’ vats, metal works, shell-ornament makers, and a bead-maker’s shop have been identified.
The architectural features seen in this major city appear throughout the vast region occupied by the Harappan civilization. The quality of the baked brick construction, the regular layout of city blocks in a rough grid plan, the extensive and well-built drainage system, and the large buildings on the “citadel” indicate a complex society fully as sophisticated as any seen in Mesopotamia and Egypt. In contrast, during the final stage of the Harappan period, Mohenjo-Daro experienced a marked deterioration in town planning and in the quality of construction.