Rain water harvesting

Read more to find out how the simple to install, rain water harvesting system sorts to resolve the problem of constant water shortage for us.

Although close to three-fourth of our planet is occupied by water, not all of it is suitable for use. The water in the oceans and seas cannot be used as drinking water and little of it can be utilized for other purposes. As a result, there is a constant shortage of water for drinking and for other home and industrial use. Modern day rain water harvesting system sorts to resolve this problem.

The idea behind the process is simple. Rain water is collected when it falls on the earth, stored and utilized at a later point. It can be purified into drinking water, used for daily applications and even utilized in large scale industries. In short, rain water harvesting is a process or technique of collecting, filtering, storing and using rain water for irrigation and for various other purposes.

Rain water harvesting 2
Rain water harvesting looks easier than it sounds.

The simplest method for a rain water harvesting system is storage tanks. In this, a catchment area for the water is directly linked to cisterns, tanks and reservoirs. Water can be stored here until needed or used on a daily basis. The roofs our homes are the best catchment areas, provided they are large enough to harvest daily water needs. Other than that, large bowls and tarps can also fulfill the function.


There are numerous ways to divert rainfall from its journey to the storm drain and instead put it to use on your property.  By starting with the basic and inexpensive options, you can get a better feel for what your yard needs, making it easier to advance your rain water harvesting system in the future.

An ideal rain water harvesting system does not capture more water than a landscape can use because water surpluses can become a nuisance if water is not utilized within two to three months.

Simple active harvesting option

If you have a roof and gutters, you’ve already accomplished a major step towards rain water harvesting. Houses with gutters generally divert the rain water falling on the roof to one main location. Place a large barrel or a drum underneath the main drain pipe to capture and store rain water.

Make sure the container you choose has an external pipe and a valve so you can connect a hose to water your plants as well as shut off the water coming from the barrel. Also, remember to keep your gutters free of twigs and leaves so the gutters can continue to direct the flow of water to the downspout.

Rain water harvesting
A large barrel for capturing rain water from drain pipe.

Lastly, make the system even more efficient by placing the rain water collection container on a raised platform so as to receive the added benefit of gravity. By elevating the barrel, gravity helps maintain the pressure in the hose so you can irrigate plants further from the collection and storage point.

Simple passive harvesting option

In a simple system, rain water is put to immediate use and consists of a catchment area (the roof) and a means of distribution (gravity).

Rain water flows from the roof but instead of collecting in barrels via gutters, rain water falls from the roof into a dug hollow path. The dug path then channels the rain water towards a holding area where the landscape plants or the vegetable garden utilize the diverted water.

An added benefit of passive systems is erosion control. By keeping more water on-site, less water and soil flush out into the street during storm.


  1. Easy to maintain: The overall cost of rain water harvesting system installation and operation is much lesser than that of water purifying or pumping systems. Maintenance requires little time and energy.
  2. Reducing water bills: Water collected in the rain water harvesting system can be put to use for several non-drinking functions as well. For many families and small businesses, this leads to a large reduction in their utilities bill.
  3. Suitable for Irrigation: Rain water is free from many chemicals found in ground water, making it suitable for irrigation and watering gardens.
  4. Reduces Demand on Ground Water: With an increase in population, the demand for water is also continuously increasing. The end result is that many residential colonies and industries are extracting ground water to fulfill their daily demands. This has led to the depletion of ground water which has gone to significant low level in some areas where there is huge water scarcity.
  5. Can be Used for Several Non-drinking Purposes: Rain water when collected can be used for several non-drinking functions including flushing toilets, washing clothes, watering the garden, washing cars etc. 
Rooftop rain water harvesting


Problems associated with rain water harvesting include: unpredictable rainfall which can limit the supply of rain water; initial high set-up cost; storage limits- during the heavy downpour, the collection systems may not be able to hold all the rain water; stagnant water may become breeding ground for insects.


  • It is recommended to divert the initial flow of run-off water to waste in order to reduce the concentration of contaminants significantly.
  • Improved water quality can also be obtained by using a floating draw-off mechanism rather than drawing water from the base of the tank.
  • An ideal rain water harvesting system does not capture more water than a landscape can use because water surpluses can become a nuisance if water is not utilized within two to three months.

Happy Gardening

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