A Beginner's Guide To Rainwater Harvesting

Rainwater harvesting is the practice of collecting and storing rain for reuse, rather than letting the water run off and be absorbed into the ground or channelled into drains, streams, or rivers. It is one of the easiest ways to conserve water at home while also lowering your bills.

The practice of rainwater harvesting is gaining new relevance as the impacts of the climate crisis accelerate and parts of the world experience drier and longer droughts, depletion of groundwater, and freshwater pollution from saltwater flooding.

Rainwater harvesting provides a source of clean fresh water in places where water is scarce, polluted, or only seasonally available. In addition, harvesting and storing rainwater can be a less expensive way (compared to desalination or piping water long distances) to guarantee safe, clean water for drinking and home use, as well as gardening, watering livestock, or agriculture.

While there are all kinds of modern rainwater catchment systems, collecting rain is an ancient practice. Anthropologists believe that being able to capture and store water went hand-in-hand with the development of agriculture, especially in drier environments. Cisterns for storing rainwater have been found in communities as far back as Neolithic times, and by 2500 BC they could be found in what is now Israel and the Greek island of Crete, and later in the Roman Empire, Istanbul, and even Venice.

How it works: capture, store, reuse

The most basic rainwater harvesting systems include a way to collect the rain (which could be as simple as the roof of a house), a way to direct the water (like a gutter and downspout), and a place to store the water (like a barrel). Because it lacks filtration and proper storage, water collected from a system this simple would only be suitable for basic uses like watering a garden, fire suppression, or as grey water – like toilet bowl water.