Harappan drainage system

Topic: Harappan (Sindhu-Sarasvati) Civilisation · NCERT: Class 6, Ch 6 "The Beginnings of Indian Civilisation"; Class 12, Ch 1 "Bricks, Beads and Bones"

Meaning

The Harappan drainage system was a planned network of covered brick drains. It carried dirty water from nearly every house, through a sump or cesspit (a small pit that trapped solid waste), into the street drains. It matters because it shows that Harappan towns were planned in advance and that people cared about cleanliness. The archaeologist Mackay called it "the most complete ancient system as yet discovered."

Explanation

Background: a city planned before it was built

• Harappan towns were laid out first and lived in later.
• Streets followed a grid pattern, crossing each other at right angles.
• Streets and drains were laid first, and houses were built after them.
• So the drains were part of the original plan.

• They were not added later to an already crowded town.

• Houses stood on mud-brick platforms that were raised before building began. At Mohenjo-daro, these platforms alone took about 4 million person-days of labour.

• Bricks followed one standard ratio, 4:2:1 (length:breadth:height). This helped builders lay drains and houses to the same pattern at sites far apart.

Main features

• House connections
• Most houses had their own brick-paved bathroom.

• A drain from the bathroom ran out to the street drain.

• Materials

• The main channels were made of bricks set in mortar (a paste that binds bricks together).

• Covers

• The drains were covered with bricks, and sometimes with limestone slabs.

• These covers could be lifted, so the drains could be cleaned.

• Sumps and cesspits

• Waste water passed into a sump or cesspit before it reached the street drain.
• Solids settled at the bottom of the pit, so only the water flowed on.
• Sumps were also placed at intervals along long channels.

How it worked

• Flow path: house drain → sump or cesspit → street drain.
• Solid waste stayed in the pits, which stopped the channels from getting blocked.
• Because the covers could be removed, workers could reach the drains and the pits to clean them.
• At the Great Bath in Mohenjo-daro, waste water left the tank through a large corbelled drain. Its roof was made of bricks, each set a little further in than the one below, until the two sides met [2].

Results and significance

• Towns stayed cleaner, and dirty water was kept off the streets.
• Small settlements had it too. Lothal had mud-brick houses but drains of burnt brick. So good drainage was a common standard, not something only big cities had.
• Many historians see this level of planning as a sign of a strong central authority, even though no palace or king has been found.

Time, place and evidence

• Period: the Mature Harappan phase, c. 2600–1900 BCE. The civilisation as a whole dates to c. 3500–1300 BCE.
• Key sites:
• Mohenjo-daro (Sindh, Pakistan): the clearest example, with house drains, street drains and the Great Bath's corbelled drain [2].
• Harappa (Punjab, Pakistan): followed the same planned layout.

• Lothal (Gujarat): burnt-brick drains alongside mud-brick houses.

• Key person: Ernest Mackay, an archaeologist who excavated at Mohenjo-daro. He described the drainage as "the most complete ancient system as yet discovered."

• How we know: from archaeological excavation of the drains, sumps, bathrooms and street layouts. No Harappan text describes the system, because the Harappan script has not been read.
• NCERT: Class 6, Ch 6 "The Beginnings of Indian Civilisation"; Class 12, Ch 1 "Bricks, Beads and Bones".

Don't confuse with

• Great Bath (Mohenjo-daro): a single ritual tank in the Citadel. It was made watertight with gypsum mortar and bitumen [2]. It had its own outflow drain, but it was a special building, not the town's general waste-water network.
• Dholavira water management: used to collect and store water, not to remove waste. It had at least six reservoirs, the largest about 73 m long, linked by underground drains and fed by two seasonal streams [2][3].
• Wells of Mohenjo-daro (~700): these supplied clean water to the town. The drains removed dirty water. One brought water in, the other took it away.
• Canal irrigation at Shortughai (Afghanistan): possible canals for farming, found only at this site. These are not drains, and no confirmed canals exist in the Indian core zone.

Prelims Hooks

• Mackay described the Harappan drainage as "the most complete ancient system as yet discovered."
• Order of flow: house drain → sump or cesspit → street drain.
• Drain covers were removable bricks or, sometimes, limestone slabs. They were lifted to clean the drains.
• Trap: the drains were laid before the houses, not added later. This is evidence of a planned city.
• Lothal (Gujarat): mud-brick houses but burnt-brick drains, so drainage was found even at smaller sites.
• The Great Bath's waste water went into a large corbelled drain [2].

Mains Points

• Evidence of planning:
• Drains were laid before houses, and the brick ratio was 4:2:1 at every site.

• This supports the "planned city" view over the "gradual accretion" view (the idea that towns grew slowly without a plan).

• Authority without kings:

• Building a drainage network across a whole city, and keeping it clean, needed organised labour and some civic body to run it.

• Yet no palaces have been found. This feeds the debate about how Harappan society was governed.

• Cleanliness and society:

• Private bathrooms connected to public drains show that cleanliness was valued in ordinary homes.
• Compare contemporary Mesopotamian cities, which were built around temples. Harappan towns put their effort into public works like drains instead. This is useful for GS-I answers on Indian heritage.

Related concepts

• Harappan town planning
• Citadel
• Lower Town
• Upper town and lower town
• Harappan bricks
• Harappan domestic architecture
• Mohenjo-daro
• Great Bath of Mohenjo-daro
• Warehouse of Mohenjo-daro
• Dholavira reservoirs

Read more

• Town planning, architecture and water management