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What are the Different Methods of Rain Water Harvesting?

Dan Cavallari
Dan Cavallari

Rain water harvesting can be done simply with a barrel and a hose, or it can involve a larger, more elaborate system that stores water in an underground tank for everyday use in the home. In areas where water is of high value, catching rain water is one of only a few options for obtaining usable water, so larger, more elaborate rain water harvesting systems may be used. Gardeners, however, may use a simple barrel and hose system that gives them more water to use on the garden or lawn.

A ground catchment system is used in areas where water is scarce. It is a difficult method to set up correctly, though if it is done correctly, it can catch a significant amount of water. The system works by collecting rain water and runoff from higher elevations. The water is set to flow through a filtering system, usually consisting of rocks, sand, and other filtering materials; it is then allowed to flow into a basin for storage. The water can then be funneled into homes or wells for use. It is one of the rarer forms of rain water harvesting, and it is not common in areas that get regular rainfall.

A wooden barrel can be used to collect rainwater.
A wooden barrel can be used to collect rainwater.

A rain harvesting system that is more common on individual homes is the rooftop collecting system. A concrete catchment is built on the roof of a home, and a series of gutters and pipes moves water down to a tank on the ground level. The water is then filtered and stored in a clean underground tank. It is pumped into the home through yet another filter before use inside the home. Such rain water harvesting systems can be expensive to set up, and they require regular cleaning and maintenance to prevent disease and contamination from insects and animals.

Gutters can be used to channel water from a house's roof.
Gutters can be used to channel water from a house's roof.

Simpler rain water harvesting systems for the lawn or garden require a small investment of time and money to set up, and they can be used for watering lawns or gardens, or for other purposes around the yard. The most common rain water harvesting system for such purposes is simply a large plastic or metal barrel with a filter on top. Rain water can be collected in the barrel, which has a spigot on the bottom so a garden hose can be attached to it. If the barrel is placed under a gutter or a rain water drip chain, it will collect even more water more quickly. Water collected in such a system should not be used as drinking water unless it is properly sterilized.

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Discussion Comments


@Ana1234 - It might be worth looking at the different techniques that are being pioneered around the world, particularly in areas where rainfall is not constant.

Rain water harvesting in India, for example, can be very advanced, but simple at the same time. Often the only thing they really need help with is the sanitation aspect, in order to have a perfect water supply.


@bythewell - That's pretty awesome. It's something that I wish a lot more places would do, because in a lot of places we are starting to have serious water shortages and they are only going to get worse in the next few decades.

Part of the problem is that people are using too much water from the reservoirs. When you take into account all the water that goes to irrigation and industry it adds up to a lot.

But part of the problem is also that cities are made up of so much concrete, it's impossible for rain water to trickle into the ground like it should. It often goes straight back to the nearest river, or the ocean.

If there was more rainwater harvesting, that would be water that didn't get washed away and that didn't get drawn out of the reservoirs.


One of our local high schools did a project recently where they got one of the senior classes to work out how to install rain water harvesters and then follow the idea through to the conclusion.

So they raised funds for the project and bought a couple of water tanks and they installed them and had an expert from the local university come in to teach them about keeping the water safe and testing it and everything.

It was a really cool project and it had components from lots of different subjects in it (like chemistry for testing the water, social science for planning consent and so forth). The best thing is that they can be really proud about getting their school essentially "off the grid" for water supplies from something they did.

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    • A wooden barrel can be used to collect rainwater.
      By: Brad Pict
      A wooden barrel can be used to collect rainwater.
    • Gutters can be used to channel water from a house's roof.
      By: stocksolutions
      Gutters can be used to channel water from a house's roof.