The History of Rainwater Harvesting

When you consider the range of high tech rain harvesting equipment available today - from specialty diverters that remove debris from the water before it reaches the tank, to the high strength resin tanks that can hold hundreds or thousands of gallons, to powerful electric pumps that put the water right where we need it - it’s tempting to think of rain harvesting as something new. But in fact, capturing and storing rainwater in cisterns goes back thousands of years - to the neolithic age, when waterproof lime plaster cisterns were built into the floors of homes in Southeast Asia. 

By 4000 bce, rainwater storage tanks were a crucial component of the emerging water management techniques used in dry-land farming.

Ancient cisterns have been discovered in Israel, including one dating to around 2500 bce with a storage capacity of 60,000 cubic feet. It had been carved from solid rock, and lined with large stones sealed with clay to ensure it stayed watertight.

During the Minoan period (2,600 - 1,100 bce) large cisterns were used on the island of Crete to collect and store rainwater, including one at Myrtos-Pyrgos dating from 1700 bce, with a capacity of over 2,400 cubic feet. 

Around 300 bce, farming communities in what is now Pakistan, Afghanistan, Iran, and India harvested rainwater for agriculture and other uses. Notable collection tanks in this region include the Shivaganga tank, which collected rainwater from the Brihadeeswarar temple in Indai, and the Vīrānam tank, which was 16 km long and had a capacity of 1,465,000,000 cubic feet.

Romans excelled in rainwater harvesting and built entire cities with the infrastructure to divert rainwater into large cisterns to be used for drinking, bathing, washing, irrigation, and livestock. In Pompeii, rooftop water storage cisterns were commonly used before construction of the aqueducts in the first century bce, and for centuries, Venice depended on rainwater harvesting, because the lagoon that surrounds the town is brackish and undrinkable.

The ancient residents of Venice built insulated collection wells that allowed water to percolate down specially designed stone flooring where it was filtered by a layer of sand, then collected at the bottom of the cistern. Later Venice imported water by boat from nearby rivers, but these storage tanks were vital for times when the city was under siege by an enemy and cut off from the mainland. 

The enormous Sunken Palace cistern, in modern day Istanbul, was made to capture rainwater from the streets above, and still exists today. It’s so large that boats can sail in it.

In the 16th century, the terms ‘soft’ and ‘hard’ water were coined by early settlers of North America, who began to use rainwater for laundry instead of mineral-rich ‘hard’ water. When they washed with ‘hard’ water, the soap would react, causing a build-up to occur, unlike when they used soft rainwater, The harvested rainwater allowed the soap and dirt to wash off much more easily than the hard water, which reacted with the soap, causing build-up.

In fact rainwater harvesting was so important in certain frontier areas, that both settlers and natives would not have been able to survive without it.