Rainwater harvesting, just like the name suggests, is the collecting and storing of rainwater before it reaches the ground. A cistern or tank collects the diverted runoff from a roof structure. If you treat it properly, you use it the same way  you use well water or municipal water. This process is one of the oldest methods of collecting water and is budget-friendly. Read on to learn all about rainwater harvesting.

History of Rainwater Harvesting

Historians trace the process back to 4000 BCE in what we call Mesopotamia. We believe that the Mesopotamians developed cisterns to collect the rainwater. This process allowed ancient humans to transform from a life of hunters and gatherers to a more agricultural society. Although the oldest evidence of rainwater harvesting is in Mesopotamia, this was common among many ancient civilizations throughout the world.  The Roman Empire frequently used rainwater harvesting and brought the technology to all the corners of its empire.  After the fall of the Roman Empire, subsequent civilizations and empires continued to use rainwater harvesting for their needs as well.

How Can We Use This Process?

Rainwater harvesting has many uses.  The most common uses are for agricultural purposes.  Since high amounts of salinity destroy agriculture crops, the low levels of salinity in rainwater is a benefit to crop growth.  Additionally, in some developing countries, they use rainwater for laundry, toilets, cooking, and bathing.


The benefits of rainwater harvesting are many.  Since the rainwater os collected before touching the ground, it reduced water runoff, thus reducing agricultural soil waste through erosion.  If used as a supplemental source of water, it can reduce the cost associated with running a private well or drawing from a municipal source.  Rainwater harvesting reduces the amount of well usage thus giving the aquifer time to regenerate in both quantity and quality.  Buildings that are built with a harvesting structure also tend to be cooler and therefore more energy-efficient than building built without.  Lastly, for the most part, the mechanism to harvest rainwater is easy to build and install and relatively cheap.


As of now, rainwater harvesting is best as a supplement to either municipal water or well water.  The major limitation of the process is not having control over access to the water.  If a severe drought or dry spell occurs, then you might not be able to get the water if you do not have any other means for water access.  Another limitation is that to harvest enough rainwater for large-scale use, the system to collect the water will need to be larger and therefore might become cost-prohibitive.  Lastly, although less susceptible to bacteria and other contaminants found in groundwater, rainwater can still be contaminated from air pollution and while in a collection pool, can attract insect larvae and microorganisms that can cause illness.  At the end of the day, even rainwater that is harvested still needs to be treated for human consumption.